1 


TABLE  OF  CONTENTS 

Section  Page 

Introduction,           5 

I.     General  Railway  Signal  Electric  Inter- 
locking System, 13 

II.     General  Railway  Signal  Electric  Inter- 
locking Appliances, 29 

III.  General    Railway  Signal   Alternating 

Current  Appliances, 107 

IV.  Signal  Lighting  at  Interlocking  Plants,  125 
V.     Electric  Locking  and  Check  Locking, .  131 

VI.     Installation   and   Operating   Data  for 

Power  Plants  and  Switchboards, .     .  143 
VII.     Installation    and  Operating   Data  for 

Electric  Interlocking  Machines,    .     .  183 
VIII.     Installation   and    Operating  Data  for 

Switch  Mechanisms, 197 

IX.     Installation   and    Operating  Data   for 

Signal  Mechanisms, 235 

X.     Installation    and   Operating   Data  for 

Relays  and  Indicators, 263 

XL     Installation   and   Operating   Data  for 

Transformers, 277 

XII.     Installation    and   Operating  Data  for 

Primary  Batteries, 283 

XIII.  Wire,  Trunking,  and  Conduit,  ...  295 

XIV.  Portland  Cement  Concrete,     ....  319 
XV.     Written  Circuits, 329 

XVI.     Signal  Aspects  and  Symbols, ....  341 

XVII.     General  Data, 361 

XVIII.     Appendix,      . 403 

Index, .419 


ELECTRIC 
INTERLOCKING 
HANDBOOK  | 

BY  THE 

ENGINEERING  STAFF  OF  THE 

GENERAL  RAILWAY  SIGNAL  COMPANY 

WITH  AN  INTRODUCTION  BY 

WILMER  W.  SALMON 


HENRY  M.  SPERRY,  EDITOR 
M.  Am.  Soc.  C.  E. 

PAUL  E.  CARTER,  ASSISTANT  EDITOR 
SHERMAN  A.  BENEDICT,  ILLUSTRATOR 


PRICE  $3.00 


GENERAL  RAILWAY  SIGNAL  COMPANY 

ROCHESTER,  N.  Y. 
1913 


COPYRIGHT,  1913,  BY 

GENERAL,  RAILWAY  SIGNAL.  CO. 

ROCHESTER,   N.  Y. 


THE  ENGINEERING  STAFF 

OF  THE 
GENERAL  RAILWAY  SIGNAL  COMPANY 


WINTHROP  K.  HOWE,  CHIEF  ENGINEER 

M.  A.  I.  E.  E. 

FRANK  L.  DODGSON,  CONSULTING  ENGINEER 
WILLIAM  S.  HENRY,  PRINCIPAL  ASSISTANT  ENGINEER 

JAMES  B.  EVANS,  ASSISTANT  ENGINEER 

SEDGWICK  N.  WIGHT,  COMMERCIAL  ENGINEER 

SALISBURY  M.  DAY,  ELECTRICAL  ENGINEER 


264319 


GENERAL  RAILWAY  SIGNAL  COMPANY 

WILMER  W.   SALMON, 
PRESIDENT  AND  GENERAL,  MANAGER 

GEORGE  D.  MORGAN,  CLARENCE  H.  LITTELL, 

VICE-PRESIDENT  SECRETARY 

PRINCIPAL  OFFICE  AND  WORKS 
ROCHESTER,  N.  Y. 


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CANADIAN   AGENCIES 

GENERAL  RAILWAY  SIGNAL  COMPANY  OF  CANADA,  LTD. 
LACHINE,  P.  Q. 
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WELLINGTON,  N.  Z., AUSTRALASIA  CHAMBERS 


GENERAL   RAILWAY    SIGNAL   COMPANY 

ENGINEERS,  MANUFACTURERS,  AND  ERECTORS  OF 

RAILWAY  SIGNAL  APPLIANCES 


PRODUCTS 

ELECTRIC  INTERLOCKING 

MECHANICAL  INTERLOCKING 

AUTOMATIC  BLOCK  SIGNALS,  DIRECT  CURRENT 

AUTOMATIC  BLOCK  SIGNALS,  ALTERNATING  CURRENT 

MANUALLY  OPERATED  BLOCK  SIGNALS 

TELEPHONE  SELECTORS 


INTRODUCTION 

INTERLOCKING  is  of  English  origin,  numerous  patents 
having  been  granted  in  England  for  manually  operated 
interlocking  devices  from  1856  to  1867,  at  which  later 
date  was  first  disclosed  by  Saxby  a  satisfactory  means  for 
obtaining  what  is  now  known  as  "preliminary  latch  locking." 
The  rapidity  with  which  this  valuable  system  was  adopted  in 
England  is  indicated  by  the  fact  that  six  years  later,  in  1873, 
13,000  mechanical  interlocking  levers  were  employed  on  the 
London  &  Northwestern  Railway  alone,  at  which  time  not  a 
single  lever  was  in  use  in  the  United  States,  the  first  experi- 
mental installation  having  been  made  in  this  country  by 
Messrs.  Toucey  and  Buchanan  at  Spuyten  Duyvil  Junction,  New 
York  City,  in  1874,  and  the  first  important  installations  on  a 
commercial  basis  having  been  made  by  the  Manhattan  Elevated 
Lines  of  New  York  City  with  machines  of  the  Saxby-Farmer 
type,  built  by  the  Jackson  Manufacturing  Co.  of  Harrisburg, 
Pa.,  in  1877-78. 

Very  soon  after  American  railways  had  gained  a  little  experi- 
ence with  mechanical  interlocking  plants,  it  was  felt  that 
there  were  many  situations  where  great  .economies  could  be 
effected  and  more  satisfactory  operation  obtained  if  switches 
and  signals  could  be  successfully  worked  by  power  instead  of 
manually.  For  precisely  the  same  reason  —  viz :  saving  of 
labor  —  that  English  railways  were  first  led  to  concentrate  in 
a  single  frame  the  theretofore  widely  separated  levers  for  the 
operation  of  switches  and  signals  —  thus  leading  up  to  the 
idea  of  interlocking  —  so  the  much  higher  cost  of  labor  in  the 
United  States  than  in  England  caused  the  American  railways 
to  demand  an  interlocking  that  would  afford  means  for  operat- 
ing switches  and  signals  over  greater  distances  and  with  fewer 
operators  than  were  required  under  the  English  method. 
The  first  concrete  response  of  the  American  inventor  to  this 
demand  was  the  Hydro-Pneumatic  Interlocking  installed 
in  1884  near  Bound  Brook,  N.  J.,  at  the  crossing  of  the 
P.  &  R.  and  L.  V.  R.  R.  From  1884  to  1891,  eighteen  Hydro- 
Pneumatic  plants,  having  482  levers,  were  installed  on  six 


GENERAL  RAILWAY  SIGNAL  COMPANY 


railways,'  but  th4s^  system  Ibaving  developed  many  serious 
defec_vs,^  its^ipveiitOFS  devised  and  in  1891  installed  the  first 
elecfro-piteumatk  *p1ft& .  if ^fre.  ^Chicago  &  Northern  Pacific 
Drawbridge,  Chicago.  In  the  following  ten  years,  there 
were  ordered  —  up  to  June  1,  1900  —  fifty-four  electro- 
pneumatic  plants,  having  1,864  levers,  for  use  on  thirteen 
railways.  It  was  felt  at  this  time  that  while  power  interlock- 
ing had  been  proven  to  be  usable  with  advantage  in  a  few 
important  situations,  it  fell  far  short  of  accomplishing  all  that 
was  desired  and  required  of  it  by  the  railways,  and  it  was  even 
then  believed  by  some  engineers  that  owing  to  certain  defects 
and  limitations  inherent  in  the  electro-pneumatic  principle 
itself,  some  safer,  more  reliable  and  economical  system  would 
have  to  be  developed  before  power  interlocking  could,  with 
wisdom,  be  more  generally  employed. 

Just  at  this  time  (May,  1900)  a  company  was  formed  to 
develop  and  exploit  the  electric  interlocking  patents  now 
owned  by  the  General  Railway  Signal  Company  and  embody- 
ing the  now  well-known  "dynamic  indication"  principle.  In 
1901  this  Company  put  in  service  its  first  electric  interlocking 
plant  employing  the  dynamic  indication,  at  Eau  Claire,  Wis., 
on  the  C.  St.  P.  M.  &  O.  R'y.  As  might  have  been  expected, 
in  view  of  the  newness  of  the  idea,  and  of  the  Company  exploit- 
ing it  in  opposition  to  an  old-established  and  rich  competitor, 
its  progress  was  slow;  but,  the  idea  being  right,  its  progress 
has  been  steady  and  sure,  with  the  result  that  in  the  eleven 
years  since  its  first  plant  went  into  service,  it  has  furnished  for 
use  on  eighty-three  railways  in  thirty-five  States  and  Provinces 
of  the  United  States  and  Canada,  440  of  these  plants,  having 
21,370  levers.  In  the  sixteen  years  from  the  installation  of  the 
first  commercial  pneumatic  machine,  during  which  time  no 
competitive  power  interlocking  machine  was  on  the  market, 
the  average  annual  sales  were  four  and  five-tenths  machines 
and  147  levers.  In  the  eleven  years  following  the  installation 
of  the  first  commercial  dynamic  indicating  electric  interlock- 
ing machine,  and  in  competition  with  all  other  types  of 
power  interlocking,  our  average  annual  sales  have  been 
forty  machines  and  1,943  levers.  With  but  few  exceptions, 
American  railways  requiring  power  interlocking  now  exclu- 
sively specify  the  "all  electric,"  and  while  the  success  achieved 
with  our  "dynamic  indication"  system  has  led  a  number  of 


ELECTRIC  INTERLOCKING   HANDBOOK 


companies  to  devise  and  offer  electric  systems,  it  is  believed 
conservative  to  state  that  much  more  than  90  per  cent,  of 
all  the  electric  interlocking  in  use  in  the  United  States  is  of 
our  manufacture.  A  more  exact  statement  of  percentage 
cannot  be  given  for  the  reason  that,  so  far  as  we  have  been 
able  to  ascertain,  other  makers  of  power  interlocking  plants 
have  not  in  recent  years  seen  fit  to  give  publicity  to  the  num- 
ber of  power  plants  and  power  levers  installed  by  them,  though 
prior  to  our  advent  in  this  field  such  statements  were  fre- 
quently published.  It  can,  however,  be  positively  stated 
that  more  of  our  electric  plants  and  more  electric  levers  have 
been  installed  on  American  railways  in  this  past  ten  years 
than  of  all  other  types  of  power  interlocking  in  the  past  twenty- 
eight  years. 

An  evolution  so  rapid,  extensive  and  radical  as  this  cannot 
fail  to  suggest  an  inquiry  into  its  causes  and  what  bearing 
they  may  or  should  have  upon  the  interlocking  practice  of  the 
future. 

During  the  annual  meeting  of  the  Railway  Signal  Associa- 
tion at  Buffalo  in  October,  1901,  one  of  the  principal  questions 
discussed  was,  "At  what  leverage  is  it  economical  to  install 
power  interlocking  rather  than  mechanical."  The  consensus 
of  opinion  then  seemed  to  be  that  power  plants  might  be 
economically  used  where  and  only  where,  on  account  of  the 
size  of  the  machine  or  density  of  traffic  or  for  any  other  reason, 
more  levermen  would  be  required  to  operate  a  mechanical 
than  a  power  machine.  At  that  time  the  writer  hazarded 
the  opinion  that  in  the  course  of  time  mere  size  of  plant  and 
density  of  traffic  would  cease  to  be  generally  regarded  as  the 
sole  or  even  as  very  vital  factors  in  arriving  at  a  choice  between 
power  and  mechanical  interlockings ;  that  signalmen  who  were 
at  that  time  obliged  to  compare  the  advantages  of  mechanical 
interlocking  with  those  of  the  only  power  interlocking  with 
which  they  then  had  experience,  the  electro-pneumatic,  might 
reasonably  be  expected  to  change  their  views  very  materially 
when  they  came  to  be  familiar  with  the  advantages  of  "all 
electric"  interlocking.  How  far  this  forecast,  which  was  then 
regarded  by  many  able,  experienced  signalmen  as  visionary, 
was  warranted  may  be  judged  by  an  examination  of  tables  in 
this  handbook  showing  hundreds  of  small  and  medium  sized 
electric  interlocking  plants  installed  by  us  in  the  decade  that 


8  GENERAL  RAILWAY   SIGNAL  COMPANY 

has  elapsed  since  then,  thus  affording  evidence  that  not  only 
is  electric  interlocking  rapidly  displacing  all  other  types  of 
power  interlocking  but  that  it  is  being  largely  and  increasingly 
used  where  formerly  nothing  but  mechanical  interlocking 
would  have  been  considered.  The  writer  believes  now  as  he 
believed  ten  years  ago  that  certain  of  the  important  reasons 
for  this  change  are  found  in  the  following  facts: 

Entirely  aside  from  considerations  of  economical  operation 
that  obviously  demand  the  usage  of  power  interlocking  at  all 
points  where  more  than  one  leverman  would  be  required  for 
the  operation  of  a  mechanical  plant,  or  where  train  movements 
are  so  numerous  as  to  make  the  operation  of  such  a  plant  too 
great  a  physical  strain  upon  the  operator,  there  are  other  and 
equally  important  features  to  be  considered  with  respect  to 
every  proposed  new  interlocking,  chief  of  which  is  the  fact 
that  no  purely  mechanical  interlocking  ever  devised  is  any- 
where near  so  safe  as  is  the  dynamic  indicating  electric  inter- 
locking. In  spite  of  the  now  general  recognition  of  this  fact, 
it  must  be  remembered  that  it  was  only  as  the  electric  inter- 
locking came  to  be  commonly  used  and  its  safety  features  to 
be  compared  with  those  of  straight  mechanical  interlocking 
that  the  defects  and  dangers  of  the  latter  became  emphasized 
by  the  contrast.  Thus,  beginning  about  ten  years  ago,  the 
realization  of  this  fact  by  skilled  signalmen  led  them,  at  first 
slowly  but  as  time  has  gone  on  more  and  more  rapidly,  to  one 
'of  two  practices,  viz:  the  use,  on  the  one  hand,  of  electric 
interlocking,  pure  and  simple,  or,  on  the  other,  adding  to 
mechanical  interlocking  all  sorts  of  electrical  apparatus  and 
circuits.  Where  the  latter  expedient  is  adopted,  the  resultant 
composite  plant  requires  a  maintainer  combining  the  experience 
of  a  mechanic  and  of  an  electrician,  and  such  men  are  not 
numerous.  Fifteen  years  ago  the  number  of  young  men  who 
had  even  a  rudimentary  knowledge  of  electrics  was  small; 
but — owing  to  the  enormously  increased  employment  of  elec- 
tricity in  telegraphy,  telephony,  lighting,  manufacturing  and 
transportation;  to  the  institution  of  simple  courses  in  elec- 
tricity in  trade,  industrial  and  correspondence  schools;  and  to 
the  fact  that  it  is  easier  and  takes  much  less  time  to  acquire 
a  usable  working  knowledge  of  electrics  than  to  become  a 
fairly  skilled  mechanic  —  most  railways  now  find  it  possible 
to  procure,  at  the  prevailing  wage  rate,  men  capable  of 


ELECTRIC   INTERLOCKING   HANDBOOK 


maintaining  electrical  rather  than  mechanical  installations  — 
particularly  since  the  automobile  and  kindred  industries  have 
created  such  an  unprecedented  demand,  at  high  wages,  for 
mechanics. 

Another  fact  having  an  important  bearing  on  this  phase  of 
our  subject  is  this :  American  block  signal  practice,  like  its 
interlocking  practice,  was  originally  copied  from  the  English, 
who  employed  the  manual  system.  In  block  signaling,  as  was 
the  case  in  interlocking,  the  American  demand  for  labor 
saving  devices  early  led  to  the  invention  of  power  operated 
automatic  block  signals,  the  first  of  which  to  be  employed 
on  a  considerable  scale  were  of  the  pneumatic  type.  Now, 
in  automatic  block  signaling,  as  in  interlocking,  the  electric  is 
almost  entirely  supplanting  the  electro-pneumatic,  and  few,  if 
any,  American  railways  are  now  considering  anything  but 
electric  signals  for  new  block  work.  Such  signals  are  now 
used  on  upwards  of  35,000  miles  of  American  railway,  and 
large  additions  are  being  made  thereto  annually.  It  will 
hardly  be  denied  by  any  engineer  skilled  in  signaling  that 
every  interlocking  plant  located  in  automatic,  electric,  block 
signaled  territory  should  be  electric,  since,  if  for  no  other 
reasons,  it  can  be  more  simply  installed,  more  economically 
maintained  and  more  reliably  operated  than  a  mechanical  or 
any  other  type  of  interlocking  which  would  require  the  mixing 
in  with  the  necessary  electric  block  devices  of  other  types  of 
apparatus  requiring  maintainers  and  repairmen  having  needed 
training  in  two  or  more  trades  rather  than  in  one.  This  is  a 
consideration,  which,  quite  apart  from  that  of  maximum 
safety,  has  led  many  railways  to  the  installation  of  a  great 
deal  of  electric  interlocking  in  automatic  block  signaled  dis- 
tricts and  which  is  influencing  them  and  others  to  take  like 
action  where  automatic  block  signaling,  though  not  in  imme- 
diate prospect,  may  be  put  in  within  a  few  years. 

Thus  it  has  come  to  pass  that  of  the  railway  men  who  still 
feel  that  the  mechanical  interlocking  when  provided  with 
various  electrical  adjuncts  may  be  made  to  be  almost  if  not 
quite  as  safe  as  the  "all  electric  plant,"  more  and  more  are 
coming  to  realize  that  simplicity,  economy  and  reliability 
demand  the  usage  of  the  electric  interlocking  in  preference  to 
any  others,  particularly  as  a  mechanical  plant,  even  when 
equipped  with  the  most  elaborate  system  of  electrical  adjuncts, 


10  GENERAL   RAILWAY   SIGNAL   COMPANY 

has  not  changed  its  nature  but  still  remains  a  mechanical 
plant,  subject  to  most  of  the  operating  difficulties  inseparable 
from  such  a  plant. 

Another  situation  that  has  largely  influenced  the  adoption 
of  electric  interlocking  is  the  following:  Up  to  the  time  of 
the  introduction  of  electric  interlocking,  it  was  the  rule,  rather 
than  the  exception,  for  American  railways  to  operate  from 
interlocking  machines  at  ordinary  crossings  and  junctions 
such  switches  as  were  within  700  to  800  feet  of  it,  but  not  to 
operate  or  adequately  signal  more  distant  switches.  Where 
any  connection  existed  between  such  distant  switches  and 
the  interlocking  it  was  usually  no  more  than  that  established 
by  having  an  electric  circuit  controller  on  such  a  switch  by 
means  of  which  an  electro-magnetically  slotted  distant  signal 
alone  was  prevented  from  giving  its  proceed  indication  when 
the  switch  was  open  between  it  and  the  home  signal.  It 
was  claimed  by  the  railways,  not  without  reason,  that  it  was 
too  difficult  and  costly,  and  in  some  instances  impossible,  to 
satisfactorily  operate  such  switches  from  a  single  machine 
and  that  it  would  be  the  height  of  folly  for  them  to  install  one 
or  more  additional  machines  merely  for  the  sake  of  operating 
these  switches,  the  interlocking  of  which  would  not  have  been 
at  all  considered  at  the  moment  except  for  their  proximity  to 
junctions  or  crossings  they  were  obliged  to  interlock.  Gradu- 
ally, however,  for  one  or  another  reason,  American  practice  is 
coming  more  and  more  approximate  to  that  of  England, 
where  every  main  line  switch  on  a  passenger  carrying  road  has 
to  be  properly  signaled  and  interlocked,  and  coincident  with 
and  probably  largely  responsible  for  this  changed  attitude  of 
the  American  railways  is  the  now  almost  universal  recognition 
of  the  fact  that  electric  interlocking  alone  affords  the  means  for 
successfully  accomplishing  this  in  the  United  States  without 
excessive  cost  for  both  installation  and  operation.  Many  of 
our  electric  plants  have  for  years  satisfactorily  operated 
switches,  together  with  their  allied  signals,  located  from  one 
to  six  thousand  feet  from  the  interlocking  machine,  some- 
times with  tunnels  or  other  obstructions  to  view,  intervening 
between  the  interlocking  station  and  the  switches.  In  fact, 
as  temperature  changes,  no  matter  how  great  or  how  sudden, 
do  not  in  any  degree  affect  the  operation  of  our  electric 
plants,  they  being  absolutely  free  from  such  disorders  as,  in  a 


ELECTRIC   INTERLOCKING   HANDBOOK  11 

mechanical  plant,  occur  because  of  contraction  or  expansion  of 
parts  connecting  the  interlocking  levers  with  the  switches 
and  signals,  and  as  the  "dynamic  indication"  features  and  the 
"illuminated  track  diagrams"  make  it  wholly  unnecessary  for 
the  operator  to  see  tracks,  trains,  switches,  or  signals  —  there 
is  absolutely  no  limit  to  the  distance  at  which  such  switches  and 
signals  can  be  safely,  reliably  and  expeditiously  worked  by  means 
of  our  electric  interlocking.  As  an  illustration,  it  may  be 
of  interest  to  note  here  that  by  far  the  largest  interlocking  plant 
in  the  world,  one  of  our  dynamic  indicating  type,  at  the  Grand 
Central  Terminal  of  the  N.  Y.  C.  &  H.  R.  R.  R.,New  York  City, is 
operated  most  successfully  under  conditions  where  it  is  impos- 
sible to  have  any  view  from  the  interlocking  station  of  trains, 
tracks,  switches,  or  signals. 

It  would  be  possible,  as  is  recognized  by  all  who  have  closely 
observed  and  carefully  studied  the  trend  of  American  signal 
practice  for  a  score  or  more  of  years,  to  cite  almost  number- 
less additional  conditions  each  of  which  has  had  some  part, 
big  or  little,  in  determining  why  it  is  that  electric  interlocking 
has  been  and  is  being  increasingly  installed  in  units  varying 
all  the  way  from  four  to  four  hundred  levers;  why  it  is 
used  with  equally  satisfactory  results  at  small  junctions, 
yards  and  crossings  where  traffic  is  light ;  at  hundreds  of 
points  of  medium  traffic  where  machines  of  from  sixteen 
to  forty-eight  levers  are  required  and  at  the  busiest  and 
largest  terminals ;  but  such  a  citation  would  be  long,  and  after 
all,  the  whole  matter  can  be  briefly  summed  up  by  saying  that 
the  reasons  why  more  of  our  dynamic  indicating  electric  inter- 
locking machines  have  been  installed  in  the  last  ten  years 
than  of  all  other  types  of  power  interlocking  in  the  past  twenty- 
eight  years,  and  why  they  are  being  so  largely  employed 
where  formerly  only  mechanical  machines  would  have  been 
considered  are  —  that  experience  has  fully  demonstrated  that 
wherever  and  under  whatever  conditions  of  traffic  or  climate 
our  dynamic  indicating  electric  system  has  been 'tried  it  has 
been  found  superior  to  every  other  type  of  interlocking,  in 
safety,  reliability,  economy  and  rapidity. of  operation  and  in 
its  adaptability  to  every  present  and  prospective  need  of  the 
user.  For  these  reasons,  the  writer  hazards  the  prediction 
that  within  the  next  ten  years  many  important  American 
railways  will  closely  approximate  to  a  condition  where  every 


12  GENERAL  RAILWAY  SIGNAL  COMPANY 

block  signal  and  every  interlocking  machine,  large  and  small, 
over  long  stretches  of  their  main  line  will  be  controlled,  operated 
and  lighted  by  power  supplied  from  central  energy  stations, 
and  where,  in  consequence,  mechanical  or  any  other  than 
electric  interlocking  will  be  almost  as  much  a  thing  of  the 
past  as  is  the  "horse  car"  on  the  street  railways  of  to-day. 
To  such  readers  as  may  be  inclined  to  regard  this  forecast  as 
wild  or  visionary,  the  writer  suggests  the  perusal  of  the  preface 
prepared  by  him  for  the  1902  Electric  Interlocking  Catalogue, 
and  that  this  may  be  readily  done,  that  preface  is  reprinted 
herein  (see  page  405).  After  noting  the  forecasts  made  in 
1902  and  finding  that  every  claim  therein  advanced  for  the 
then  newly  introduced  electric  interlocking  system  has  been 
fully  met  and  that  its  general  adoption  has  more  than  realized 
the  most  sanguine  expectations  then  entertained  for  it  —  the 
reader  may  be  less  inclined  to  be  over  skeptical  as  to  the  pre- 
diction made  for  the  coming  decade. 

To  meet  the  requirements  of  the  many  present  and  prospec- 
tive users  of  our  dynamic  indication  electric  interlocking,  we 
have  prepared  this  Handbook,  wherein  it  is  sought  to  furnish 
data  that  will  be  useful  to  all  those  seeking  a  true  understanding 
of  the  dynamic  indication  principle,  and  to  those  who  are 
required  to  prepare  bills  of  material  for,  or  to  install,  operate 
or  maintain  our  electric  interlocking. 

W.  W.  S. 


SECTION  I 


G.  R.  S.  ELECTRIC    INTERLOCKING    SYSTEM 


SETTING  FORTH  THE  PRINCIPLES  IN- 
VOLVED AND  GIVING  A  BRIEF  DE- 
SCRIPTION OF  THE  APPLIANCES  USED 


G.  R.  S.  ELECTRIC  INTERLOCKING 
SYSTEM 

REQUISITES  OF  A  PROPERLY  DESIGNED  INTERLOCKING 

SYSTEM 

INTERLOCKED  switch  and  signal  appliances  were  first  de- 
vised and  used  at  junctions  and  terminal  points  for  the  pur- 
pose of  reducing  the  number  of  men  employed  to  go  from 
switch  to  switch,  throw  them  by  hand  and  then  give  a  hand  sig- 
nal for  the  train  to  proceed  over  the  route  thus  lined  up.  It  was 
soon  found  that  operating  the  switches  and  signals  from  a  central 
point  under  the  control  of  the  levers  in  an  interlocking  machine 
greatly  expedited  the  handling  of  traffic.  By  far  the  greatest 
accomplishment  of  interlocking,  however,  was  the  addition  of 
an  enormous  factor  of  safety  at  such  points  to  train  operation. 

Inherent  in  the  system  of  mechanical  interlocking  which 
first  was  employed  to  control  the  switch  and  signal  functions 
were  certain  recognized  shortcomings  as  regards  safety  and 
facility  of  operation. 

Systems  of  power  interlocking  in  the  field  prior  to  the  intro- 
duction of  the  electric  dynamic  indication  system,  now  owned 
and  manufactured  by  the  General  Railway  Signal  Company, 
although  giving  increased  facility  of  operation,  did  not  and 
do  not  provide  the  greatest  safety  obtainable  with  this  increased 
facility. 

The  features  of  vital  importance  in  considering  the  merits 
of  any  system  of  power  interlocking  are  those  which  are 
designed  to  give  the  greatest)*  measure  of  safety  together  with 
facility  of  operation.  The  two  features  most  important  to 
safety  are : 

First  —  The  means  provided  to  check  the  correspondence 
of  movement  between  lever  and  the  switch,  signal,  or  other 
function  controlled  by  it. 

Second  —  The  means  for  preventing  unauthorized  move- 
ment of  switches,  signals,  or  other  controlled  functions. 

The  reliability  of  the  means  by  which  the  above  protection  is 
secured  determines  more  than  anything  else  the  safety  of  a 
given  system  of  interlocking.  In  fact,  this  is  so  vital  that  an 
interlocking  plant  without  a  thoroughly  dependable  system 
for  insuring  correspondence  between  its  levers  and  the  operated 
functions,  and  for  preventing  the  unauthorized  movements  of 
such  functions,  is  absolutely  unsafe. 

The  G.  R.  S.  electric  interlocking  system  fully  meets  the 
first  important  requirement  of  checking  the  correspondence  of 
movement  between  lever  and  operated  function  by  means  of 
the  dynamic  indication,  energy  for  which  is  furnished  by  a 
momentary  dynamic  current  generated  by  the  motor  of  the 
operated  function  itself  when  and  only  when  the  actual  opera- 
tion of  such  function  shall  have  been  properly  completed. 
Contrast  this  with  systems  employing  A.  C.  or  battery 


16 


GENERAL  RAILWAY  SIGNAL  COMPANY 


indication,  in  which  the  indication  is  secured  from  energy 
existent  at  the  function  prior  to  and  during  the  movement  of 
that  function  and  dependent  only  on  the  closing  of  a  single 
break  in  the  indication  circuit. 

The  use  of  the  dynamic  current,  generated  by  the  momen- 
tum of  the  motor  of  the  operated  unit  at  one  end  of  the  circuit 
and  so  giving  the  desired  indication  at  the  lever  at  the  other  end 
of  the  circuit,  prevents  the  receipt  of  a  false  indication  due  to  a 


FIG.  1. 


LAKE  STREET  INTERLOCKING  PLANT. 
TERMINAL,  C.  &  N.  W.  R'Y 


CHICAGO 


cross  between  the  wires  of  the  circuit,  and  is,  therefore,  correct 
in  principle. 

The  unauthorized  movement  of  switches  or  derails,  or  the 
improper  clearing  of  the  signals  is  prevented  by  a  simple  and 
effective  method  of  cross  protection,  the  basis  for  which  is 
inherent  in  an  electric  interlocking  system  using  dynamic 
indication.  It  is  a  notable  feature  that  the  second  require- 
ment is  met  by  a  means  in  which  all  the  contacts  required  for 
this  protection  form  a  part  of  the  operating  circuit,  thus  check- 
ing their  integrity  at  each  operation. 

In  order  to  fully  consider  the  advantages  of  the  G.  R.  S. 


ELECTRIC  INTERLOCKING  HANDBOOK 


17 


system  of  electric  interlocking,  its  elements  are  described  in 
more  detail  as  outlined  below. 

ELEMENTS  OF  G.  R.  S.  ELECTRIC  INTERLOCKING 

SYSTEM 

A  complete  installation  of  the  General  Railway  Signal  Com- 
pany's electric  interlocking  system  comprises  the  following 
elements : 

First  —  A  source  of  power  consisting  of  a  storage  battery 
with  its  charging  unit. 


FIG.  2.    COLLIN-W 


3RLOCKING    PLANT.        L.    S.   &  M.   S.   R*Y 


Second  —  Power  control  apparatus  introduced  between  the 
source  of  power  and  the  interlocking  machine. 

Third  —  An  interlocking  machine  with  levers  for  the  control 
of  the  switch  and  signal  mechanisms. 

Fourth  —  Switch  mechanisms,  their  operating  and  indicat- 
ing circuits. 

Fifth  —  Signal  mechanisms,  their  operating  and  indicating 
circuits. 

Sixth  —  Means  for  the  prevention  of  unauthorized  move- 
ment of  any  function. 

In  connection  with  such  a  system  may  be  installed  such 
accessories  in  the  way  of  track  circuits,  detector  locking, 
route  locking,  indicators,  annunciators,  etc.,  as  may  be  de- 
sired at  each  individual  installation. 


18 


GENERAL  RAILWAY  SIGNAL  COMPANY 


SOURCE  OF  POWER 

The  source  of  power,  from  which  the  G.  R.  S.  system 
of  electric  interlocking  is  operated,  consists  of  a  storage 
battery  having  an  approximate  working  potential  of  110 
volts,  this  battery  being  charged  by  a  power  generating 
unit,  which  frequently  is  a  generator  driven  by  a  small 
gasoline  engine. 


FIG.  3.     MODEL  2  UNIT  LEVER  TYPE  INTERLOCKING  MACHINE. 

LAKE  STREET  INTERLOCKING  PLANT,  CHICAGO 

TERMINAL,  C   &  N.  W.  R'Y 


POWER  CONTROL  APPARATUS 

Power  is  delivered  to  the  interlocking  machine  under  the 
control  of  protective  apparatus,  mounted  on  suitable  switch- 
boards. 

INTERLOCKING  MACHINE 

The  operation  of  each  switch  and  signal  function  is  controlled 
by  levers,  which  with  their  respective  locking  tappets,  indica- 
tion magnets  and  circuit  controllers,  are  mounted  in  a  common 
frame,  the  whole  being  known  as  an  interlocking  machine. 

Starting  with  the  lever  in  either  of  its  extreme  positions, 
the  stroke  of  the  lever  is  divided  into  two  movements.  The 
first  movement  locks  all  levers  conflicting  with  its  new  position 
and  operates  the  function.  The  second  and  final  movement 


ELECTRIC    INTERLOCKING    HANDBOOK 


19 


of  the  stroke  releases  such  levers,  hitherto  locked,  as  do  not 
conflict  with  its  new  position.  Except  in  the  reverse  position 
of  a  signal  lever,  this  final  movement  can  be  made  after,  and 
only  after,  the  dynamic  indication  has  been  received  certifying 
that  the  operated  function  has  assumed  a  position  correspond- 
ing with  that  of  its  lever. 

SWITCH  MECHANISM  —  ITS  OPERATING  AND  INDICATING 
CIRCUITS 

Each  switch  and  derail  is  thrown  and  locked  by  a  switch 
and  lock  movement  driven  by  a  series  wound  direct  current 


FIG.  4. 


MODEL  4  SWITCH  MACHINES      HIGH  BRIDGE,  TOWER  "A," 
ELECTRIC  DIVISION,  N.  Y.  C.  &  H.  R.  R.  R. 


motor.  Two  wires  are  used  for  its  control,  one  for  the  normal 
and  the  other  for  the  reverse  operation.  These  same  wires 
are  used  for  indicating  purposes,  the  normal  control  wire  being 
used  for  the  reverse  indication  and  the  reverse  control  for  the 
normal  indication.  The  circuit  is  connected  to  main  common 
at  the  switch  location. 

The  circuits  for  a  switch  are  shown  in  simplified  form  in 
Fig.  5,  the  operating  and  indicating  currents  in  the  different 
diagrams  being  shown  by  the  red  lines. 

When  the  switch  (normal  position)  is  to  be  operated,  the 
first  movement  of  the  stroke  of  the  controlling  lever  carries  it 
as  far  as  the  reverse  indication  position  and  permits  current  to 
flow  as  shown  in  Fig.  5B,  which  causes  the  mechanism  to  move 
the  switch  points  to  the  reverse  position  and  lock  them  in 
that  position.  When  this  movement  has  been  completed  the 


20 


GENERAL   RAILWAY   SIGNAL  COMPANY 


5viiich  Mechanism 
'  Motor-Veld   " 


Main   Common 


Reverse  Control  &  •* 
Normal  Ind  rti 


lever  Full  Normal  5nitch  Mormal 

A  -  At  Rtst-  No  Current  floning 


Lever 

Indication  Position 


B  -  Operdting 


Snitch  leaving 
Normal  Position 


Lever  at  Reverse 
Indication  Position 
C  -  Indicating 


5nitch  Reverse 


• Til — 5P   ^* 


Lever  Full  Reverse  Snitch  Reverse 

D  -   At  Rest-  No  Current  flowing 

FIG.  5.     SIMPLIFIED  CIRCUITS  FOR  MODEL  2  OR  MODEL  4 
SWITCH  MACHINE 


ELECTRIC   INTERLOCKING   HANDBOOK 


21 


circuit  through  the  switch  motor  is  automatically  changed, 
disconnecting  the  motor  from  battery  and  connecting  it  in  a 
closed  circuit  including  the  indication  magnet  (Fig.  5C) ;  at  the 
same  time  the  armature  terminals  are  reversed  for  indication 
purposes,  this  leaving  the  motor  connections  in  proper  position 
for  the  next  operation.  The  motor  (now  a  generator)  with 
the  momentum  acquired  during  the  operation  of  the  switch 
movement,  generates  a  momentary  current  which  energizes 


FIG.  6. 


MODEL  2  SWITCH  MACHINES.     MAYFAIR  INTERLOCKING 
PLANT,  C.  &  N.  W.  R'Y 


the  indication  magnet,  thus  permitting  the  final  movement  of 
the  lever  to  be  completed  (Fig.  5D). 

The  operation  of  the  lever  and  function  from  the  reverse  to 
the  normal  position  is  accomplished  in  the  same, manner. 

A  useful  feature,  not  usually  obtainable  in  other  power  sys- 
tems, is  that  the  movement  of  the  switch  points  may  be  re- 
versed at  any  portion  of  their  travel  at  will  by  the  operator, 
and  the  lever  movement  completed  upon  the  switch  points 
assuming  a  position  corresponding  with  that  of  the  lever, 
irrespective  of  the  direction  of  the  first  movement  made  by 
the  lever. 

The  complete  switch  operation  and  final  movement  of  the 


22 


GENERAL  RAILWAY   SIGNAL  COMPANY 


lever  may  be  accomplished  in  from 
two  to  two  and  one-half  seconds, 
the  indication  being  practically 
instantaneous  with  the  completion  of 
the  switch  operation. 


SIGNAL  MECHANISM  —  ITS  OPERA- 
TING AND  INDICATING  CIRCUITS 

The  description  of  signal  mechan- 
isms will  be  confined  to  the  non- 
automatic,  two  position  signal,  as  this 
will  show  the  principles  involved  in 
all  types  of  motor  driven  signals  now 
used  in  the  system. 

This  signal  is  operated  by  a 
mechanism  in  which  the  motor  is 
directly  connected  to  the  semaphore 
shaft  through  low  reduction  gearing. 
The  signal  is  held  at  proceed  during 
such  time  as  its  controlling  lever  is 
in  the  reverse  position  solely  by  a 
dense  magnetic  flux  thrown  across 
the  air  gap  between  the  motor  arma- 
ture and  the  field  pole  pieces  (holding 
field  pole  surfaces  are  serrated)  by 
cutting  the  windings  on  the  holding 
field  poles  in  series  with  the  operating 
field  windings. 

Each  signal  requires  for  its  opera- 
tion and  indication  one  wire  and  a 
connection  to  the  common  return  wire. 
A  simplified  circuit  for  this  type  of 
signal   is   shown  in   Fig.  8,  the  path 
taken  by  the  operating,  holding,  and 
indicating  current  in  the  different  dia- 
grams being  shown  by  the  red  lines. 
Upon  reversal  of  the  controlling  lever,  the  signal 
mechanism  will  receive  current  as  shown  in  Fig.  8B, 
this  causing  it  to  move   the   blade  to  the  proceed 
position.     When  the  signal  blade  has  assumed  this 
position  the  circuit  breaker  cuts  in  series  with  the 
operating   field    and    armature,   the    high-resistance 
holding  field,  thereby  retaining  the   signal   arm  at 
proceed  (Fig.  8C).     The  holding  field  windings  have 
a  high  resistance,  which  reduces  the  current  to  that 
employed  for  holding  the  signal  at  proceed. 

When  the  signal  lever  is  placed  in  the  normal  indicating 
position,  energy  is  cut  off  from  the  motor  and  the  blade  returns 
to  the  stop  position  by  gravity,  causing  the  signal  mechanism 
and  motor  armature  to  revolve  backward  to  their  original 


ELECTRIC   INTERLOCKING   HANDBOOK 


23 


Mechanism 


R         N 


Control  and  Indication 


FT 

T-T   Indication 
I |[[l.lil     1 


rloldinb 
Field  — 


;0pen 
>  Field 


Mam   Common 


Motor  __ 
Armature 


Lever  full  normal  5'tyial  at  stop 

A  -  At    rest -no   current  flowing 

R         M 


^Ulll 


Lever  -full   reverse 


Lever  -full   reverse 


-    Operating 


C   -    Holding 


LJ 


Signal    leaving  stop   position 


Signal    or    proceed 


Lfi 


Lever    at   normal 
indicating    position 


.    ,n<jicat,n^ 


lO'(Approx) 
from    stop    position 


'LJ 


Lever    full    normal 

E-  At  rest  -no   current 


Signal   at  stop 


FIG.  8.     SIMPLIFIED  CIRCUITS  FOR  MODEL  2A,  NON-AUTOMATIC, 
Two  POSITION  SIGNAL 


24  GENERAL   RAILWAY   SIGNAL  COMPANY 


position.  Just  as  the  blade  reaches  the  stop  position  the 
action  of  the  circuit  breaker  connects  the  motor  armature  and 
operating  field  into  their  original  closed  circuit  (Fig.  8D),  in 
which  is  included  the  indication  magnet.  Due  to  its  acquired 
momentum  the  motor  (now  a  generator)  produces  an  indica- 
tion current  in  this  circuit  which  permits  the  controlling  lever 
to  be  moved  to  the  full  normal  position  (Fig.  8E). 

It  is  universal  practice  to  indicate  the  signal  lever  in  the 
normal  position  only,  this  insuring  that  the  signal  blade  is  in 
the  stop  position  before  releasing  any  of  the  switch  levers  in 
the  route  governed.  No  safety  features  are  sacrificed  if  the 
signal  fails  to  assume  the  proceed  position  upon  reversal  of  its 
controlling  lever. 

Dynamic  Indication.  The  use  of  the  dynamic  indication  as 
described  above  has  the  following  advantages  : 

First  —  The  indication  is  not  secured  from  energy  existent 
at  the  function  prior  to  the  movement  of  that  function  and 
dependent  only  on  the  closing  of  a  single  break  in  the  indica- 
tion circuit,  as  is  the  case  in  A.  C.  and  battery  indication 
systems;  but  being  a  dynamic  current  generated  by  the  mo- 
mentum of  the  motor,  it  can  be  secured  only  after  actual  opera- 
tion of  the  function. 

Second  —  The  energy  for  the  indication  is  developed  at  one 
end  of  the  circuit  and  the  indication  magnet  is  located  at  the 
other ;  hence  a  cross  between  wires  prevents  indication,  whereas 
in  systems  which  use  the  battery  in  the  interlocking  station 
for  indication  a  cross  tends  to  cause  indication. 

Third  —  No  extra  power  is  required  for  indication. 

Fourth  —  The  indication  current  ceases  automatically  with 
the  stopping  of  the  motor  and,  therefore,  no  auxiliary  devices 
or  operations  are  necessary  to  cause  it  to  cease. 

Fifth  —  No  additional  wires  are  required  for  indication. 

Sixth  —  The  generated  indication  current  automatically 
"snubs"  the  motor  and  causes  it  to  stop  without  shock  and 
without  the  use  of  buffers,  springs,  or  auxiliary  snubbing 
circuits. 

Seventh  —  The  indicating  circuit  is  automatically  checked 
as  to  its  integrity  every  time  an  indication  is  received,  and 
being  a  closed  circuit  of  low  resistance  around  the  motor,  it 
shields  the  motor  while  at  rest  from  all  foreign  currents.  This 
inherently  provides  the  foundation  for  the  simple  and  effective 
cross  protection  system  employed  with  the  G.  R.  S.  electrie 
interlocking. 

MEANS  FOR  THE  PREVENTION  OF  UNAUTHORIZED 
FUNCTION  MOVEMENTS 

The  cross  protection  system  prevents  the  unauthorized 
movement  of  any  switch,  signal,  or  other  function  due  to 
energy  improperly  applied  to  its  circuit  through  a  cross  between 


ELECTRIC   INTERLOCKING   HANDBOOK  25 

wires,  by  cutting  off  current  from  the  function  in  the  event  of 
such  an  occurrence. 

As  explained  under  "Dynamic  Indication,"  all  functions  are 
normally  on  a  closed  circuit  of  low  resistance.  Connected  in 
each  of  these  circuits  is  a  small  polarized  relay  through  which 
all  operating  and  indicating  currents  must  pass  in  a  direction 
to  maintain  the  relay's  contact  closed,  while  all  currents  from 
an  unauthorized  source  must  pass  in  the  opposite  direction 
thus  instantly  opening  the  contact.  Through  all  these  con- 


FIG.  9.     MODEL  2A  SIGNALS.     CHICAGO  TERMINAL,  C.  &  N.  W.  R'Y 

tacts  in  series  is  controlled  the  retaining  magnet  of  an  electro- 
mechanical circuit  breaker,  which  is  introduced  into  the  power 
mains  between  the  storage  battery  and  the  interlocking  ma- 
chine. Hence,  a  cross  onto  the  circuit  of  a  function  at  rest, 
by  opening  the  contact  of  its  polarized  relay,  opens  the  electro- 
mechanical circuit  breaker,  cuts  power  off  from  the  Interlocking 
machine  and  thereby  prevents  any  improper  movement  of 
the  function. 

In  a  simple  plant  a  single  electro-mechanical  circuit  breaker 
is  ordinarily  installed,  this  preventing  the  movement  of  all 
functions  at  any  time  the  circuit  breaker  may  be  open.  Where 
traffic  conditions  warrant  the  increased  expenditure,  additional 
circuit  breakers  may  be  provided  to  permit  of  dividing  the 
plant  into  as  many  sections  as  may  be  desired. 


26  GENERAL   RAILWAY   SIGNAL   COMPANY 


The  design  of  the  circuit  breaker  is  such  as  to  make  it  impos- 
sible for  a  leverman  (thoughtlessly  or  through  ignorance)  to 
prevent  it  from  performing  its  function. 

Cross  Protection.  The  cross  protection  secured  with  the 
G.  R.  S.  electric  interlocking  system  has  the  following  advantages : 

First  —  All  contacts  and  connections  depended  upon  for 
cross  protection  are  either  on  closed  circuit  or  are  used  for  opera- 
tion and  indication,  so  that  any  failure  of  these  contacts  and 
connections,  which  would  impair  their  usefulness  as  a  cross- 
protective  medium,  also  prevent  operation  and  indication. 
Hence  they  are  under  a  constant,  automatic  check  without  the 
use  of  any  extra  contrivances  for  this  purpose. 

Second  —  Wire  insulation  is  not  depended  upon  for  cross 
protection.  This  system  at  certain  installations  has  given 
years  of  safe  operation  with  wire,  the  insulation  of  which  does 
not  measure  up  to  the  usual  standard. 

Third  —  The  cross  protective  apparatus  consists  of  the  polar- 
ized relays  and  apparatus  on  the  operating  board;  no  wire  or 
additional  appliances  are  required  outside  of  the  station  to 
secure  this  protection  other  than  the  simple  apparatus  already 
installed  for  the  operation  of  the  various  functions. 

Fourth  —  The  switch  and  signal  motors,  being  of  low  resist- 
ance, require  a  current  of  several  amperes  for  their  operation ; 
therefore,  a  cross  to  produce  the  operation  of  any  function 
must  be  of  very  low  resistance.  Thus  it  will  be  seen  that  the 
system  is  not  sensitive  to  the  effect  of  crossed  wires.  Not- 
withstanding this  fact,  an  efficient  system  of  cross  protection 
is  provided  in  the  G.  R.  S.  system. 

CONCLUSION 

The  comparative  value  of  different  systems  of  interlocking 
may  be  accurately  determined  by  a  consideration  of  but  four 
essential  factors.  These  four  factors  must  be  present  in  any 
interlocking  system  to  warrant  its  use.  They  are:  Safety, 
Facility,  Reliability,  and  Economy. 

Safety. 

The  factor  first  demanding  consideration  is  that  of  safety. 
This  essential  of  an  interlocking  system  overshadows  all  other 
considerations,  and  in  the  ideal  system  the  safety  must  be 
absolute.  The  G.  R.  S.  electric  interlocking  with  dynamic 
indication  provides  a  factor  of  safety  that  is  the  closest  approxi- 
mation to  the  ideal  known  to  those  skilled  in  the  signaling  art. 
This  is  verified  by  the  statement  made  by  a  disinterested 
committee  in  an  able  report  based  on  a  study  of  various  types 
of  power  interlocking  systems,  presented  to  the  International 
Congress  of  Application  of  Electricity  held  at  Marseilles, 
France,  in  1908,  this  statement  being  worded  as  follows: 

"The  safety  of  an  interlocking  plant  is  dependent  solely 


ELECTRIC   INTERLOCKING   HANDBOOK  27 

upon  the  existence  of  a  positive,  reliable  indication  of  corre- 
spondence between  the  position  of  a  lever  and  its  controlled 
function.  *  *  *  the  Taylor  (G.  R.  S.)  system  meets 
even  this  requirement.  In  fact  it  insures  absolute  reliability 
of  indication  by  employing  the  motor  as  a  means  for  generat- 
ing the  required  current  as  explained  above  —  so  that  it  is 
certain  that  the  indication  given  cannot  ever  be  due  to  de- 
fects in  wiring.  Then,  this  indication  having  been  received 
in  the  interlocking  station,  it  establishes  a  control  which  is 
permanently  maintained  by  a  source  of  energy  located  in 
the  station.  Moreover  this  permanent  control  utilizes  identi- 
cally the  same  circuit  that  is  employed  in  the  normal  operation 
of  the  function;  in  consequence,  the  circuit  used  is  one  that 
must  be  maintained  in  good,  operative  condition  for  each 
movement  of  the  function. 

It  will  therefore  be  seen  that  by  virtue  of  this  arrangement, 
the  Taylor  (G.  R.  S.)  system  insures  permanency  of  indica- 
tion ;  that  it  is  economical  since  it  utilizes  the  operating  source 
of  energy  located  in  the  station,  and  that  it  is  absolutely 
trustworthy  since  it  is  in  no  sense  subject  to  any  danger  from 
crossed  or  grounded  wires." 

Facility. 

The  facility  offered  by  any  given  interlocking  system  depends 
largely  upon :  first,  the  rapidity  of  operation  of  the  individual 
functions,  and  second,  its  capabilities  for  permitting  simulta- 
neous operation  of  a  number  of  functions.  In  such  a  system 
the  amount  of  time  required  to  move  traffic  is  reduced  to  a 
minimum. 

By  incorporating  the  above  two  features  in  the  design  of  the 
system,  the  G.  R.  S.  electric  interlocking  fully  meets  all 
demands  for  facility  of  operation.  This  has  been  repeatedly 
proven  by  the  performance  of  the  system  at  points  where 
the  traffic  conditions  have  imposed  the  most  exacting  operating 
requirements. 

Reliability. 

The  reliability  of  an  interlocking  system  is  primarily  de- 
pendent upon  the  fundamental  principle  underlying  its  opera- 
tion, and  in  general  it  may  be  said,  without  fear  of  contradic- 
tion, that  unless  the  principle  is  simple,  it  is  not  correct.  The 
correct  principle  having  been  adopted,  the  reliability  of  the 
system  then  depends  upon  a  proper  design  of  each  and  every 
part  of  the  devices  used  to  put  the  principle  into  practice. 

It  is  recognized  that  the  principles  of  operation  of  the  G.  R.  S. 
interlocking  are  correct,  and  the  circuits  simple  to  an  extreme 
degree,  no  radical  changes  having  been  made  in  either  since 
the  introduction  of  the  system.  The  parts  of  all  apparatus  are 
strong  and  rugged,  and  capable  of  performing  their  functions 
without  undue  wear  and  tear;  furthermore,  the  design  of  all 
parts  of  the  apparatus  has  been  so  very  carefully  perfected 


28  GENERAL   RAILWAY  SIGNAL  COMPANY 


during  some  twelve  years'   experience  that  their  form  now 
represents  the  very  best  engineering  practice. 

As  an  example  of  the  system's  reliability  of  operation, 
records  published  by  an  important  railroad  covering  a  period 
of  one  year  show  a  total  of  2,615,406  switch  operations,  in 
which  the  number  of  imperfect  operations  were  so  few  that 
they  did  not  exceed  one  to  every  186,814,  and  the  total  traffic 
detention  for  the  year  was  only  seventy  and  one-half  minutes. 

Economy. 

Due  to  the  correct  design  of  the  apparatus  and  resultant 
long  life  of  same,  the  cost  of  renewals  is  practically  negligible. 
This,  together  with  the  marked  simplicity  of  the  circuits, 
insures  a  cost  of  maintenance  much  less  than  in  any  other 
system  of  interlocking.  The  cost  of  operating  also  shows  a 
corresponding  economy,  not  only  by  the  fewer  number  of 
men  required  for  the  operation  of  the  power  system  as  com- 
pared with  the  mechanical  system,  but  also  in  the  cost  of 
power  when  compared  with  other  power  systems.  Carefully 
kept  railroad  records  show  that  the  power  cost  is  but  one  cent 
for  300  to  400  switch  and  signal  movements. 

A  most  minute  analysis  and  extended  description  of  the 
merits  and  advantages  of  any  given  system  of  interlocking 
fails  to  be  convincing  unless  the  truth  of  all  the  statements 
are  thoroughly  substantiated.  That  the  above  statements 
concerning  the  G.  R.  S.  electric  interlocking  system  must 
be  true,  is  shown  by  the  well  nigh  universal  adoption  of  the 
system,  both  for  large  and  for  small  installations. 

Four  hundred  and  forty  installations  have  been  made  or 
are  under  contract  on  some  eighty  different  railroads  in  all 
parts  of  the  United  States  and  Canada,  a  considerable  num- 
ber of  plants  also  having  been  installed  in  Europe.  On  the 
basis  that  one  interlocking  lever  in  use  for  one  year  equals 
one  lever  year,  the  G.  R.  S.  system  now  shows  a  record  of 
110,000  lever  years. 

The  satisfactory  operation  of  these  installations,  large  and 
small,  under  widely  varying  conditions  of  both  climate  and 
traffic,  is  a  most  convincing  demonstration  that  every  demand 
for  an  interlocking  system  has  been  met  in  a  most  satisfactory 
manner  by  the  G.  R.  S.  electric  interlocking. 


SECTION  II 


G.  R.  S.  ELECTRIC    INTERLOCKING 
APPLIANCES 


GIVING    A    DESCRIPTION    OF    THE    AP- 
PLIANCES   USED    AND   THEIR    METHOD 
OF    OPERATION 


INTERLOCKING  STATIONS 
THE  INTERLOCKING  STATION 

THE  interlocking  station,  from  which  the  various  switch 
and  signal  functions  of  the  plant  are  operated,  is  usually 
a  two-story  building  similar  in  appearance  to  those  used  at 
mechanical  plants.    The  station  does  not  require  the  same  heavy 
construction  used  in  mechanical  work  on  account  of  the  fact  that 
the  movement  of  the  levers  of  the  electric  interlocking  machine 
puts  absolutely  no  strain  on  the  building.     It  should  be  noted 


FIG.  10.     HACKENSACK  DRAW  BRIDGE  INTERLOCKING 
STATION.     ERIE  R.  R. 

in  this  connection,  however,  that  the  frame  building  generally 
used  in  the  earlier  installations  is  of  late  years  being  largely 
supplanted  by  the  more  substantial  brick  or  concrete  structure. 

SIZE  OF  THE  BUILDING 

The  station  can  be  much  smaller  than  that  required  for 
mechanical  plants  of  the  same  number  of  functions  due  to  the 
smaller  size  of  the  interlocking  machine.  The  length  of  the 
building  is  usually  determined  by  the  size  of  the  interlocking 
machine;  the  width,  however,  is  generally  in  excess  of  that 
required  for  the  machine,  being  increased  to  accommodate 
the  table,  lockers,  etc.,  needed  by  the  operator,  and  on  the 


32 


GENERAL  RAILWAY  SIGNAL  COMPANY 


Jol 


\  i 

t      V       fL*           ,    - 

Desk 

D 

c 
V 

3 
j 

>-. 

«  .      "'  0"  r 

^  Front  of  Machine 

a 
It 

„,  80  Space  Unit  Lever  "type 
'    Interlocking  Machine 

'c 

f 

i 

loft'     ft" 

HO   1  —  —  jcO  •  0  1  •• 
L'  Operating  Snitch  Board 
.      m  —  ..Indicator  Cabinet 

rl  33  i    i                   ^ 

SECOND   FLOOR. 


[ 

\                      rork  Bench            /^~^\            / 
\                                              (Sfove  )          / 

v                          \_y 

\ 

t-'  n» 

/ 

Engine                              Gencrdftor 
/ 

Battery 

Cupboard 

Duct  for  nires  to                           )     *? 

Inter  locKmg  Machine^             i  ^        |      r 

Relay  Gabinet|              N  1                1     \ 

Track  Side 
FIRST    FLOOR.. 

FIG.  11.     TYPICAL  PLANS  OF  INTERLOCKING  STATION  FOR 
EIGHTY  LEVER  MACHINE 


ELECTRIC  INTERLOCKING   HANDBOOK  33 


larger  installations  to  provide  room  for  a  train  director  and 
telegraph  operator. 

When  it  is  desired  to  have  shops  and  storerooms  located 
in  the  interlocking  station,  the  machine  ceases  to  be  the 
determining  factor  in  the  size  of  the  building,  unless  the 
additional  space  for  these  rooms  is  secured  by  using  a  three- 
story  building  as  in  the  case  of  the  Lake  Street  Station 
shown  in  Fig.  13.  It  is  also  true  that  on  small  plants  the 
location  of  the  storage  battery  and  power  apparatus  in  the 
lower  story  of  the  station  is  apt  to  make  it  necessary  for 


FIG.  12.     SOUTH  ENGLEWOOD  INTERLOCKING  STATION 
AND  POWER  HOUSE,  C.  R.  I.  &  P.  R'Y 

the  building  to  have  larger  dimensions  than  those  required 
for  the  interlocking  machine. 

ARRANGEMENT  OF  APPARATUS 

The  different  methods  of  arranging  the  apparatus  in  the 
station  is  shown  by  Figs.  11,  13  and  15,  which  may  be 
taken  as  typical  of  small,  intermediate  and  large  sized  stations 
respectively.  By  reference  to  these  illustrations  it  will  be 
seen  that  the  general  practice  is  to  locate  the  interlocking 
machine,  the  operating  switchboard  and  such  accessory  appa- 
ratus as  track  diagrams,  indicators,  etc.,  on  the  top  floor,  the 
storage  battery  in  a  room  by  itself  on  the  lower  floor,  and  the 
charging  apparatus  on  the  same  floor  with  the  battery  or  in  a 
building  separate  from  the  interlocking  station. 


34 


GENERAL  RAILWAY  SIGNAL  COMPANY 


FIG.  13.     PLAN  OP  LAKE  STREET  INTERLOCKING  STATION. 
CHICAGO  TERMINAL,  C.  &  N.  W.  R'r 


ELECTRIC  INTERLOCKING   HANDBOOK 


35 


POINTS  TO  BE  NOTED 

The  design  of  the  building  should  be  such  that  the  floors 
will  be  sufficiently  rigid  to  properly  support  the  machine. 

Wherever  possible  the  general  practice  is  to  have  the  operat- 
ing room  liberally  supplied  with  windows  to  permit  the  operator 
to  have  a  clear  view  of  the  tracks  throughout  the  plant. 

It  is  highly  desirable  that  the  conduits  or  ducts  provided  for 
the  runs  of  electrical  conductors  about  the  tower  should  be 


FIG.  14. 


LAKE  STREET  INTERLOCKING  STATION-     CHICAGO 
TERMINAL,  C.  &  N.  W.  R'Y 


of  sufficient  capacity  to  have  25  per  cent,  spare  space  after 
all  wiring  is  in  place. 

No  special  foundations  are  required  for  the  apparatus  used 
in  an  electric  plant,  except  when  the  charging  generator  is 
driven  by  an  engine,  in  which  case  a  substantial  foundation 
should  be  provided  for  the  engine  so  that  the  building  will 
not  be  subjected  to  any  vibration  during  its  operation. 


36 


GENERAL  RAILWAY  SIGNAL  COMPANY 


1 

« 

i 

Cl 
Cl 

1 

c 

Cl 
Cl 

~-.>,_l 

POWER  PLANTS  AND   SWITCHBOARDS 
COMPOSITION 

THE  power  equipment  for  the  G.  R.  S.  Electric  Interlocking 
plants  is  usually  composed  of  a  storage  battery,  suitable 
means  for  charging  the  battery,  a  power  switchboard  and  an 
operating  switchboard. 


FIG.  16.     INTERLOCKING  BATTERY  (400  AMPERE  HOURS) 
INSTALLED  ON  BATTERY  RACKS 

LOCATION 

The  location  of  the  units  which  compose  the  power  plant 
varies  considerably  on  different  installations.  The  operating 
switchboard  is  always  located  in  the  operating  room,  being 
placed  whenever  possible  in  such  a  position  that  its  meters 
and  indicating  lamp  are  in  full  view  of  the  leverman  when 
manipulating  the  levers  of  the  machine.  The  storage  battery- 
is  ordinarily  located  on  the  first  floor  of  the  interlocking 
station.  The  power  switchboard  and  charging  apparatus  at 
many  installations  are  placed  in  a  room  adjacent  to  that  occu- 
pied by  the  battery,  although  building  restrictions  or  the  need 
of  space  for  workrooms  or  offices  often  make  it  necessary  to 
house  this  apparatus  in  a  building  separate  from  the  inter- 
locking station. 


38 


GENERAL  RAILWAY  SIGNAL  COMPANY 


BATTERIES 

The  interlocking  battery  usually  consists  of  one  set  of 
storage  cells  having  a  potential  of  110  volts.  A  second  or 
duplicate  battery  is  furnished  on  a  few  of  the  larger  installa- 
tions to  insure  sufficient  power  for  any  possible  emergency. 


FIG.  17. 


INTERLOCKING  BATTERY   (120  AMPERE  HOURS) 
INSTALLED  IN  BATTERY  CUPBOARD 


The  capacity  of  the  battery  used  should  be  based  on  the  num- 
ber of  function  movements  between  battery  charges  and  the 
current  used  for  all  auxiliary  apparatus. 

The  battery  as  usually  installed  comprises  fifty-five  lead 
type  storage  cells.  When  long  runs  of  conductors  between 
the  battery  and  interlocking  machine  are  necessary,  one  or 
more  cells  are  sometimes  added  to  the  battery  to  compensate 
for  the  voltage  drop  which  occurs  in  the  conductors  when- 
ever several  switch  functions  are  operated  at  the  same  time. 


ELECTRIC   INTERLOCKING   HANDBOOK  39 


This  may  also  be  taken  care  of  by  using  wires  of  larger  carry- 
ing capacity  than  would  otherwise  be  necessary. 

Low  voltage  batteries  are  frequently  installed  to  operate 
annunciators,  indicators,  relays  and  electric  locks,  and  occa- 
sionally to  serve  the  track  circuits  of  the  interlocking  plant. 
Operating  the  relays,  indicators,  etc.,  from  a  low  voltage 
battery  usually  proves  more  economical  than  to  take  current 
for  that  purpose  from  the  main  battery. 

CHARGING  APPARATUS 

The  charging  of  the  battery  is  generally  accomplished  by 
means  of  a  shunt  wound  generator  driven  by  an  electric  motor 
or  gasoline  engine.  The  generator  should  be  capable  of  de- 


FIG.  18.     G.R.S.  D.C.  GENERATOR 

livering  the  desired  current  at  any  voltage  from  110  to  160, 
the  current  output  being  determined  by  the  charging  rate 
recommended  for  the  batteries  installed.  In  'the  event  of  the 
generator  being  used  to  supply  current  for  lighting,  either 
regularly  or  in  case  of  emergency,  the  additional  capacity 
required  for  the  purpose  should  not  be  overlooked. 

When  the  generator  is  located  at  some  distance  from  the 
battery  it  is  necessary  to  take  care  of  the  voltage  drop  due 
to  the  resistance  of  the  charging  circuit,  either  by  increasing 
the  size  of  the  conductors  or  by  using  a  generator  having  a 
higher  voltage  rating. 

Whenever  current  of  suitable  voltage  and  from  a  reli- 
able source  can  be  secured  at  reasonable  rates,  its  use  is  rec- 
ommended. The  motor-driven  generator,  referred  to  above, 
is  usable  with  either  alternating  or  direct  current,  the  generator 
being  shaft  or  belt  connected  to  the  motor  as  proves  most 


40  GENERAL  RAILWAY   SIGNAL  COMPANY 


convenient.  If  the  current  supply  is  direct,  a  charging  rheostat 
can  be  used  for  the  battery  charging,  or  if  alternating,  a 
rectifier  employed. 

Charging  rheostats,  having  no  moving  parts,  are  the  simplest 
and  most  reliable  of  the  different  types  of  apparatus  which  can 
be  used  in  this  work.  They  are,  however,  very  much  less 
efficient  than  other  battery  charging  devices,  and  therefore 
should  not  be  used  when  the  cost  of  power  is  an  item  to  be 
considered. 

Motor  generator  sets  are  compact,  reliable  and,  furthermore, 
highly  efficient.  When  used  on  this  type  of  work,  they  can 


FIG.  19.     G.  R.  S.   D.  C.-D.  C.  MOTOR  GENERATOR  SET 


be  designed  for  operation  on  voltages  as  high  as  550,  the 
lower  voltages,  however,  being  recommended  as  most  satis- 
factory from  the  maintenance  standpoint. 

POWER  SWITCHBOARD 

The  power  switchboard  most  frequently  furnished  (Fig. 
20)  is  arranged  to  control  the  charging  of  one  set  of  storage 
batteries  from  an  engine  driven  generator,  and  in  conjunction 
with  the  operating  board  to  control  the  power  delivered  to  the 
interlocking  machine. 

It  may  be  placed  in  any  accessible  position  in  the  power 
house,  convenience  in  making  the  runs  of  electrical  conductors 
between  the  power  board,  the  charging  apparatus  and  the 
battery  being  considered. 

The  size  and  arrangement  of  the  power  board  for  different 
installations  is  determined  by  the  method  of  charging  the 


ELECTRIC   INTERLOCKING   HANDBOOK 


41 


batteries,  the  number  of  sets  and  voltage  of  each  battery,  and 
whether  or  not  the  board  is  to  control  any  electric  lighting 
which  may  be  installed  at  the  plant.  If  a  motor  generator 
set  is  to  be  controlled  an  additional  panel  for  its  starting  device 
can  be  mounted  on  the  switchboard  frame. 

When  the  track  circuits  in  the  plant  are  operated  from 


FIG.  20. 


STANDARD  POWER  SWITCHBOARD  FOR  ONE  GENERATOR 
AND  ONE  110  VOLT  BATTERY 


storage  batteries  or  from  transformers  located  in  the  interlocking 
station,  it  is  customary  to  serve  these  track  circuits  through 
switches  on  the  power  board. 

On  the  switchboard  shown  in  Fig.  20  are  mounted  a 
no-voltage,  reverse-current  circuit  breaker,  a  field  rheostat,  a 
voltmeter,  an  ammeter,  suitable  switches,  and  the  necessary 
fuses. 

The  no-voltage,  reverse-current  circuit  breaker,  which  is  placed 
in  the  charging  circuit  between  the  generator  and  battery,  is 
designed  to  open  in  case  the  voltage  of  the  generator  falls  below 
that  of  the  battery.  By  means  of  this  arrangement  the  charging 


42 


GENERAL  RAILWAY  SIGNAL  COMPANY 


of  the  battery  can  be  accomplished  without  the  constant  atten- 
tion of  the  maintainer,  this  permitting  inspections  to  be  made 
at  such  intervals  as  may  be  most  convenient. 


FIG.  21.     POWER  AND  DISTRIBUTING  SWITCHBOARDS  AND  MOTOR 

GENERATOR  SETS.     LAKE  STREET  INTERLOCKING  PLANT, 

CHICAGO  TERMINAL,  C.  &  N.  W.  R'Y 

The  rheostat  connected  in  series  with  the  generator  field 
permits  the  generator  voltage  to  be  accurately  regulated. 

The  voltmeter  and  ammeter  are  arranged  to  give  readings  on 
the  charging  or  discharging  circuits  as  desired. 

The  simplified  diagram  (Fig.  22)  shows  the  principles  of 
the  circuits  used  in  connection  with  this  board  and  clearly 


ELECTRIC   INTERLOCKING   HANDBOOK 


43 


POWER    SWITCH   BOARD 


FIG.  22.     SIMPLIFIED  CIRCUITS  FOR  POWER  SWITCHBOARD 


FIG.  23.     OPERATING  ROOM  AT  OREGON  SLOUGH 

DRAW  BRIDGE.     N.  P.  R'Y 
Combination  power  and  operating  switchboard  at  extreme  left. 


44 


GENERAL  RAILWAY  SIGNAL  COMPANY 


FIG.  24  FIG.  25 

STANDARD  OPERATING  SWITCHBOARD 


ELECTRIC    INTERLOCKING   HANDBOOK 


45 


illustrates  the  functions  of  the  various  devices  essential  to  the 
power  control. 

OPERATING  SWITCHBOARD 

The  operating  switchboard  shown  in  Figs.  24  and  25  is 
typical  of  those  furnished  where  all  functions  in  the  plant  are 
to  be  controlled  through  a  single  circuit  breaker.  When  the 
plant  is  sectionalized  the  board  must  be  equipped  with  addi- 
tional circuit  breakers,  one  being  required  for  each  section. 

The  apparatus  mounted  on  the  ooard  illustrated  consists 
of  the  cross  protection  circuit  breaker  with  its  indicating  red 
lamp,  a  polarized  relay,  a  ground  lamp  and  switch,  a  volt- 
meter and  an  ammeter.  A  panel  for  lighting  switches  can  be 
bolted  to  the  switchboard  frame  when  it  is  desired  to  control 
the  lighting  from  this  point. 


FROM   POWER 


FROM   POWER 
BOARD 


qpERATmG  SWITCH  JtoARp 
CIRCUIT  BREAKER 


i: 


POLARIZED 


L. 
FIG.  26. 


INTERLOCKING  MACHINE 


POSITIVE   Buss 


Trio.  Buss 


POLARIZED  RELAY  CONTACTS 


SIMPLIFIED  CIRCUITS  FOR  OPERATING  SWITCHBOARD 


Lettering  of  the  cross  protection   circuit    breaker   contacts    corresponds 
with  the  lettering  used  in  Figs.  64  and  66. 

The  dross  protection  circuit  breaker,  introduced  into  the 
power  mains  leading  to  the  interlocking  machine,  is  so  controlled 
that  in  the  event  of  current  being  improperly  applied  to  the 
circuit  of  any  function  at  rest,  the  circuit  breaker  will  open 
and  cut  all  power  off  from  the  system.  The  red  lamp  is 
arranged  to  be  lighted  at  this  time  to  call  the  leverman's  atten- 
tion to  the  fact  that  the  circuit  breaker  has  opened. 

The  design  of  the  circuit  breaker  and  its  cover  is  such  that 
it  cannot  be  prevented  from  opening  should  a 'cross  occur, 
nor  can  it  be  restored  to  its  operating  position  except  by  means 
of  the  restoring  handle. 

The  simplified  circuit  (Fig.  26),  in  which  is  included  only 
the  apparatus  essential  to  the  circuit  breaker  control,  shows 
the  retaining  magnet  of  the  circuit  breaker  controlled  through 
the  polarized  relay  on  the  switchboard  and  those  on  the  inter- 
locking machine  in  such  a  manner,  that,  should  any  of  them 
reverse  their  position,  the  circuit  breaker  will  immediately  open. 


46  GENERAL  RAILWAY  SIGNAL  COMPANY 


The  polarized  relay  on  the  switchboard  is  to  guard  against 
the  effects  of  an  accidental  cross  between  the  positive  and 
indication  buss  bars  on  the  interlocking  machine,  the  relay 
operating  in  the  same  manner  as  the  polarized  relays  which 
protect  the  various  switch  and  signal  functions. 

By  means  of  the  ground  lamp  and  switch,  the  plant  may  be 
tested  for  positive  and  negative  grounds. 

The  voltmeter  indicates  the  battery  voltage  at  the  terminals 
of  the  interlocking  machine. 

The  ammeter  shows  the  current  taken  by  the  various  func- 
tions when  they  are  being  operated.  By  observing  this  current 
reading  the  operating  conditions  of  each  function  can  be 
determined.  This  is  particularly  true  of  the  switch  functions, 
the  need  of  oiling  or  adjustment  being  readily  detected  from 
the  abnormal  amount  of  current  or  length  of  time  required  for 
their  operation. 


ELECTRIC  INTERLOCKING  MACHINES 
INTERLOCKING  MACHINE  CONTROL 

THE  interlocking  machine  used  with  the  G.  R.  S.  system 
controls  the  movement  of  switch  and  signal  functions 
through  the  medium  of  suitably  interlocked  levers,  which 
with    their  guides,  indication  magnets  and  circuit  controllers, 
are  mounted  in  the  common  frame    as   shown   in    Fig.   27. 
General  practice  is  to  furnish  an  individual  lever  for  each  signal 


LAMP    CASE 


(CATION 
[SELECTOR 


IND. MAGNET 

SAFFTY  MAGNET 


LOCKING  PLATES 


FlG.   27. 


CROSS  SECTION  OP  MODEL  2  UNIT  LEVER  TYPE 
INTERLOCKING  MACHINE 


arm  and  for  each  switch  function,  except  where  two  switches 
are  to  be  operated  together,  in  which  case  their  levers  are  rigidly 
connected  and  operated  as  a  unit. 

The  design  of  the  machine  and  the  controlling  circuits  is 
such  that  the  following  features  essential  to  safe  operation  are 
afforded : 

First  —  No  lever  can  be  moved  from  a  given  position  if  any 
other  lever,  mechanically  interlocked  therewith,  is  in  such  a 


48 


GENERAL   RAILWAY   SIGNAL   COMPANY 


position  that  its  controlled  function  will  conflict  with  the 
function  to  be  moved.  Furthermore,  due  to  the  mechanical 
locking  being  of  the  preliminary  type,  before  the  given  lever 
can  be  moved  from  its  position,  all  these  conflicting  levers 
will  be  locked  against  movement  until  such  time  as  it  is  proper 
for  them  to  be  released. 


yj 


FIG.  28.     FOUR  HUNDRED  LEVER  INTERLOCKING  MACHINE,   MODEL  2 

UNIT  LEVER  TYPE.     GRAND  CENTRAL  TERMINAL,  TOWER  "A," 

N.  Y.  C.  &  H.  R.  R.  R. 

Second  —  The  full  movement  of  any  switch  lever  cannot  be 
completed  until  the  controlled  function  has  moved  to,  and  been 
locked  in,  the  position  corresponding  with  that  of  the  lever. 
In  the  case  of  a  signal  lever  this  correspondence  of  position  is 
required  only  on  the  normal  movement  of  the  lever,  which 
can  be  completed  only  after  the  signal  arm  has  assumed 
the  stop  position. 


ELECTRIC   INTERLOCKING   HANDBOOK 


49 


Third  —  Each  function  when  in  a  position  of  rest  is  pro- 
tected against  any  unauthorized  operation  which  might  other- 
wise be  accomplished  through  current  being  wrongfully 
applied  to  its  controlling  circuits. 

In  explaining  the  operation  of  the  lever,  its  movement  is 
considered  as  being  divided  into  three  parts,  the  prelimi- 
nary, intermediate  and  final.  In  order  that  the  reader  may 
not  be  confused  on  account  of  the  lever  operation  having 
previously  been  described  as  being  performed  in  two  move- 
ments (page  18),  it  is  desired  to  point  out  that  the  pre- 


FIG.  29.  MODEL  2  UNIT  LEVER  TYPE  INTERLOCKING  MACHINE.  COLLIN- 
WOOD  INTERLOCKING  PLANT,  L.  S.  &  M.  S.  R'Y.     (See  Fig.  32) 


liminary  and  intermediate  part  usually  constitute  one  contin- 
uous movement,  it  being  necessary  to  separate  them,  however, 
when  considering  the  detail  operation  of  the  lever. 

The  following  description  is  based  on  the  operation  of  the 
switch  lever.  Each  of  these  levers  is  provided  with  a  cam 
slot,  by  means  of  which  intermittent  motion  is  transmitted  to 
its  respective  tappet  bar  and  thence  to  the  cross  locking.  In 
Fig.  30  the  dotted  circles  1  to  5  in  the  cam  slot  indicate  the 
positions  of  the  locking  tappet  roller  which  correspond  with 
the  like  numbered  position  of  contact  block  Z.  In  the  pre- 
liminary movement  of  the  lever  from  position  1  to  2,  the 
locking  tappet  is  moved  through  one-half  of  its  stroke, 
this  movement  locking  all  levers  which  conflict  with  the  new 


50  GENERAL  RAILWAY  SIGNAL  COMPANY 


position  of  the  lever  in  question ;  in  this  movement  no  change 
whatsoever  is  made  in  the  operating  circuits.  During  the 
intermediate  part  of  the  travel  from  positions  2  to  4,  the  tappet 
bar  remains  stationary  and  the  contact  block  Z  is  moved  out  of 
engagement  with  springs  YY  and  into  contact  with  springs 
XX  as  shown  in  Fig.  31,  this  setting  up  the  circuits  for  the 
operation  of  the  function.  The  lever  is  held  at  this  point, 
(position  4),  through  the  mechanical  design  of  the  lever  proper, 
until  such  time  as  the  function  having  moved  to  a  correspond- 
ing position,  generates  the  dynamic  indication  current  which 
effects  the  release  of  the  lever  and  permits  its  movement  to 
position  5.  During  this  final  movement  from  position  4  to  5, 
the  stroke  of  the  locking  tappet  is  completed,  thereby  unlocking 
all  levers  which  do  not  conflict  with  the  new  position  of  the 
operated  lever. 

The  method  by  which  the  lever  is  prevented  from  completing 
its  stroke,  until  the  controlled  function  has  moved  to  a  corre- 
sponding position  and  has  sent  in  its  indication,  is  illustrated 
by  the  following :  in  moving  from  positions  1  to  2  projection  M 
on  the  lever  coming  against  projection  K  on  latch  L,  causes 
the  latch  to  assume  the  position  shown  in  Fig.  31.  This 
brings  projection  J  on  latch  L  into  the  path  of  tooth  Q  on  the 
lever.  In  moving  from  position  2  to  4,  tooth  Q  engages  with 
cam  N,  rotating  it  to  the  position  shown  in  Fig.  31.  As  it 
passes  the  central  position  (shown  dotted  in  Fig.  31)  it  comes 
in  contact  with  dog  P  which  is  forced  under  latch  L,  thereby 
locking  the  latch  L  in  the  position  assumed.  The  lever  is 
stopped  at  position  4  by  tooth  Q  coming  against  projection  J 
on  latch  L  as  previously  explained.  The  indication  current, 
by  flowing  through  magnet  I,  lifts  armature  T  which  causes 
plunger  R  to  strike  dog  P  and  trip  it  out  from  under  latch  L. 
The  latch  L  then  drops  to  the  position  shown  in  Fig.  30, 
thereby  releasing  the  lever  and  permitting  its  final  movement 
to  be  accomplished. 

The  movement  of  the  lever  from  reverse  to  normal  is  per- 
formed in  a  similar  manner  to  that  described  above.  Atten- 
tion is  called  to  the  fact  that  once  the  lever  has  been  moved  to, 
or  beyond,  position  3,  it  can  neither  be  moved  forward  beyond 
position  4  nor  back  beyond  position  2  without  the  receipt  of 
an  indication. 

The  movement  of  the  signal  lever  is  identical  with 
that  of  the  switch  lever  except  that  no  electrical  indi- 
cation is  required  during  the  reverse  movement,  the  lever  not 
being  checked  at  position  4  due  to  a  change  in  the  design 
of  dog  P,  which  is  mechanically  tripped  at  this  point  from 
under  latch  L  by  cam  N.  The  mechanical  locking  insures  that 
before  a  signal  can  be  given  for  any  route,  that  all  switch  and 
derail  functions  in  the  route  are  thrown  to  the  proper  posi- 
tions and  locked  in  that  position,  and  that  all  opposing  signals 
are  in  the  stop  position.  No  changes  can  be  made  in  the 
position  of  any  of  these  functions  until  the  lever,  controlling 


ELECTRIC   INTERLOCKING  HANDBOOK 


51 


52 


GENERAL  RAILWAY  SIGNAL   COMPANY 


ELECTRIC   INTERLOCKING   HANDBOOK  53 


the  signal  displayed  at  proceed,  has  been  replaced  to  its  full 
normal  position. 

The  various  functions  are  protected  against  unauthorized 
movement  by  means  of  the  cross  protection  system,  as  de- 
scribed on  page  89,  the  individual  polarized  relays  which 
furnish  this  protection  being  mounted  on  the  terminal  board 
of  the  interlocking  machine.  All  lever  contacts  which  form  a 
part  of  this  cross  protection  scheme  are  used  in  the  operation 
of  the  function,  and  hence  are  checked  as  to  their  integrity 
with  every  complete  operation. 

MODEL  2  UNIT  LEVER  TYPE  INTERLOCKING  MACHINE 

The  description  of  the  interlocking  machine  following  is  based 
on  the  Model  2  Unit  Lever  Type  (Fig.  27)  which  is  considered 
the  standard  machine.  This  machine  is  a  development  of  the 
Model  2,  still  widely  used,  a  cross  section  of  this  being  illus- 
trated by  Fig.  137.  Modifications  of  the  Unit  Lever  Type 
machine  are  shown  by  Figs.  32  and  138,  the  latter  being 
furnished  when  more  contacts  are  required  for  supplementary 
circuits  than  can  be  secured  on  the  regular  lever  circuit  con- 
troller. 

The  standard  machine  essentially  comprises  the  frame,  the 
levers  with  their  guides,  indication  magnets  and  circuit  con- 
trollers, the  locking  plates  and  locking,  the  terminal  board, 
and  the  machine  cabinet. 

Frame. 

The  frame  work,  which  consists  of  a  bed,  supporting  legs 
and  brackets,  is  substantially  constructed,  thereby  insuring 
that  all  inter-related  mechanical  parts  are  maintained  in  their 
proper  relative  positions.  For  machines  having  a  capacity  up 
to  forty-eight  lever  spaces,  the  bed  is  cast  in  one  unit.  Machines 
of  over  forty-eight  levers  are  made  up  of  various  combinations 
of  beds  bolted  together  to  give  the  required  lever  spaces. 

Locking  Plates  and  Locking. 

The  locking  plates  are  securely  attached  to  the  front  of  the 
machine  frame,  being  furnished  in  tiers  to  a  maximum  of 
three,  the  number  depending  upon  the  amount  of  locking 
required  at  each  individual  plant.  A  fourth  tier  can  be 
furnished  when  necessary  by  using  a  special  form  of  leg, 
which  has  sufficient  height  to  accommodate  the  extra  tier  of 
plates. 

The  locking  plates  are  designed  with  vertical  and  horizontal 
slots,  the  locking  tappets,  one  of  which  is  attached  to  each 
lever,  being  fitted  in  the  vertical  slot  directly  beneath  its 
respective  lever.  Movement  is  transmitted  from  ^the  lever 
through  the  medium  of  the  tappets  to  the  cross  locking,  which 
slides  back  and  forth  in  the  horizontal  slots  of  the  locking 
plates.  The  dogs  used  in  the  cross  locking  can  be  furnished 
screwed  or  riveted  to  the  locking  strips,  as  desired. 


54 


GENERAL  RAILWAY  SIGNAL  COMPANY 


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ELECTRIC   INTERLOCKING   HANDBOOK 


55 


56  GENERAL   RAILWAY   SIGNAL  COMPANY 


Each  tier  of  locking  has  eight  of  these  horizontal  slots, 
and  each  of  these  slots  is  capable  of  accommodating  four 
locking  strips,  thus  giving  this  type  of  locking  bed  a  large 
capacity  as  is  indicated  by  the  fact  that  the  locking  required 
for  extremely  large  and  complicated  layouts  has  been  readily 
accommodated  in  three  tiers.  In  fact,  it  is  a  very  rare 
occurrence  that  the  fourth  tier  is  ever  required. 

By  using  locking  of  the  vertical  type  no  additional  floor 
space  is  required  beyond  that  ordinarily  taken  by  the  machine, 


FIG.  35.  UNIT  TYPE  SWITCH  LEVER  EQUIPPED 

WITH  LEVER  LOCK  AND  LAMP  CASE 

(See  Fig.  141.) 


no  matter  how  many  tiers  are  provided.  This  type  of  locking 
also  permits  ready  access  for  inspection  or  cleaning,  or  making 
any  changes  which  may  be  required. 

Levers. 

Each  lever  with  its  guide,  indication  magnet,  controllers, 
etc.,  comprises  a  complete  unit  in  the  interlocking  machine, 
the  design  being  such  that  the  unit  may  be  removed  or  replaced 
in  the  machine  without  moving  the  lever  tappet  from  the 
normal  position  or  disturbing  adjacent  levers  in  any  way.  The 
lever  guide  is  jointly  supported  by  the  top  edge  of  the  locking 
plates  and  a  longitudinal  bar  fastened  to  the  brackets,  the 


ELECTRIC  INTERLOCKING   HANDBOOK  57 


circuit  controllers  being  screwed  to  two  other  bars  which  are 
supported  by  this  same  bracket. 

The  circuit  controller  with  which  each  lever  is  equipped  can 
be  provided  with  a  maximum  of  five  tiers  of  contacts,  con- 
trolling five  normal  and  five  reverse  independent  circuits,  which 
affords  more  contacts  than  are  ordinarily  desired  for  supple- 
mentary circuits. 

The  space  required  for  each  unit  is  but  two  inches,  this 
permitting  the  complete  machine  to  occupy  less  space  length- 
wise than  other  existing  types  of  interlocking  machines,  either 
power  or  mechanical,  having  the  same  lever  capacity. 

Lamp  Case  and  Number  Plate. 

The  combined  lamp  case  and  number  plate  is  mounted  above 
each  lever,  its  base  being  attached  to  a  plate  screwed  to  the  top 
of  the  lever  guide,  and  its  top  to  the  cabinet  frame.  The  num- 
ber plate  is  designed  to  lie  at  an  angle  which  renders  it  readily 
visible  to  the  operator  when  manipulating  the  levers.  Bulbs 
and  sockets  are  furnished  only  for  such  levers  as  may  be 
specified,  generally  being  used  in  conjunction  with  some  type 
of  electric  locking  to  give  an  indication  as  to  whether  the  lever 
may  be  moved  or  not.  If  desired,  a  double  lamp  case  can  be 
furnished  to  give  two  separate  indications. 

Terminal  Board. 

The  slate  terminal  board  is  securely  attached  to  the  brackets 
on  the  rear  of  the  machine  On  this  board  are  mounted  the 
switch  and  signal  buss  bars,  the  individual  polarized  relays, 
fuses  for  the  operating  circuits,  and  the  terminal  posts  for  all 
wires  which  form  a  part  of  any  of  the  interlocking  machine 
circuits.  The  wires  running  from  the  binding  posts  to  the 
various  contacts,  etc.,  in  the  machine  are  made  up  as  formed 
leads,  thus  presenting  a  neat  and  uniform  appearance ;  it  also 
simplifies  any  "connecting  up  "  incidental  to  the  field  installa- 
tion of  additional  levers  to  the  machine. 

All  fuses  and  terminal  posts  on  the  board  are  located  directly 
beneath  their  respective  levers,  the  terminal  posts  being 
lettered  in  correspondence  with  the  circuit  plan  to  indicate 
the  wires  which  are  to  be  attached  to  each  post. 

Polarized  Relay. 

The  polarized  relay  which  is  illustrated  by  Fig.  36  is 
mounted  on  the  terminal  board  directly  beneath  its  lever. 
It  is  provided  with  a  soft  iron  core  which  lies  lengthwise  between 
the  poles  of  a  permanent  magnet,  the  design  being  such  that 
current  passing  in  one  direction  through  a  winding  on  the 
soft  iron  core,  tends  to  hold  the  relay  armature  normal  and 
contact  closed,  while  current  in  the  opposite  direction  imme- 
diately reverses  the  armature  and  thereby  causes  the  contact 
to  open.  An  extension  of  the  armature  is  provided  for  con- 


58  GENERAL   RAILWAY   SIGNAL   COMPANY 

venience  in  replacing  it  to  the  normal  position  should  it  for 
any  cause  be  reversed 

Indication  Selectors. 

The  indication  selectors,  one  of  which  is  used  in  connec- 
tion with  each  switch  function,  are  mounted  on  a  shelf  sup- 
ported by  a  bracket  on  the  rear  of  the  interlocking  machine. 
The  selector  is  simple  in  design,  consisting  of  two  electro 
magnets  and  a  contacting  armature  which  throws  in  one 
direction  when  the  lever  is  reversed  and  in  the  other  when  the 
lever  is  put  normal. 


FIG.  36.     POLARIZED  RELAY 

INTERLOCKING  MACHINE  ACCESSORIES 
Lever  Locks. 

The  electric  lever  lock,  illustrated  by  Fig.  35,  may  be 
applied  to  any  lever  in  the  machine,  its  winding  being  designed 
for  operation  on  direct  or  alternating  current.  The  lock  is 
designed  to  be  mounted  on  the  top  of  the  lever  guide,  locking 
the  lever  in  any  required  position  by  means  of  a  solenoid 
plunger,  which,  when  the  lock  is  de-energized,  drops  into  a 
notch  cut  on  the  top  of  the  lever.  These  notches  may  be 
arranged  so  that  the  lever  will  be  locked  in  any  position  as 
required  by  the  electric  locking  circuits  used  at  the  plant. 
The  circuit  for  the  lock  coil  is  broken  through  a  contact  spring 
actuated  by  the  lever  latch,  the  lock  therefore  not  consuming 
energy  except  when  lever  is  to  be  moved. 

Mechanical  Time  Release. 

The  mechanical  time  release  furnished  with  the  G.  R.  S. 
interlocking  is  illustrated  by  Fig.  37,  and  the  method  of  its 
application  to  the  machine  by  Fig.  38.  It  is  used  in  connec- 
tion with  electric  locking  circuits  to  effect  the  release  of  a 
route  in  case  of  emergency,  this  being  accomplished  by  manipu- 
lating the  release  to  its  full  reverse  position,  at  which  point  a 
contact  is  closed  to  pick  up  a  stick  relay,  energize  a  lever  lock, 
etc.  The  first  movement  of  the  device  towards  the  reverse 


ELECTRIC   INTERLOCKING   HANDBOOK 


59 


position,  however,  mechanically  locks,  in  their  given  positions 
the  levers  controlling  all  functions  in  the  route,  this  necessitat- 
ing that  the  release  be  returned  to  its  normal  position  before 
the  route  can  be  changed.  The  operation  of  the  please  to  the 
reverse  position  and  back  to  the  normal  position  affords  a 
time  interval  of  about  two  minutes. 


FIG.  37 
MECHANICAL  TIME  RELEASE 


SWITCH  OPERATING  MECHANISMS 
SWITCH  MACHINE  CONTROL 

SWITCH  and  derail  functions  in  the  G.  R.  S.  system  are 
operated  by  switch  and  lock  movements,  driven  by  series 
wound  direct  current  motors. 

These  switch  mechanisms,  each  of  which  is  under  the  con- 
trol of  a  lever  in  the  interlocking  machine,  require  for  their 
operation  two  wires  only,  one  being  used  for  the  normal 
and  the  other  for  the  reverse  operation.  These  same  wires 
are  used  for  indicating  purposes,  the  normal  control  wire  being 
used  for  the  reverse  indication  and  the  reverse  control  for  the 
normal  indication.  The  circuit  is  connected  to  main  common 
at  the  switch  location. 

When  the  lever  is  moved  to  a  position  to  cause  the  operation 
of  the  switch  mechanism  (see  dotted  position  of  lever  con- 
tacts in  Fig.  39),  current  is  taken  from  the  positive  buss 
bar  through  the  safety  magnet,  indication  selector,  lever 
contacts  and  the  control  wire,  through  the  switch  motor 
and  to  common.  This  causes  the  desired  movement  of 
the  switch  machine,  which  performs  the  following  functions  in 
the  order  given : 

First    —  The  detector  bar  is  raised  and  the  switch  unlocked, 

Second —  The  switch  points  thrown, 

Third  —  The  switch  points  locked  and  the  bar  lowered, 

Fourth  and  Lastly  —  Current  is  cut  off  from  the  motor,  and 
the  terminals  of  the  motor  armature  reversed  for  indication 
purposes,  this  leaving  the  motor  properly  connected  for  the 
next  movement. 

The  motor  is  now  on  a  closed  circuit  which  includes  the 
indication  magnet.  Due  to  the  momentum  acquired  during 
the  switch  operation,  the  motor  armature  continues  on  several 
revolutions  for  the  generation  of  the  momentary  current 
which  energizes  the  indication  magnet  and  thereby  permits 
the  final  movement  of  the  lever  to  be  completed. 

The  operation  of  the  switch  machine  in  the  opposite  direc- 
tion is  accomplished  in  the  same  manner  as  described  above. 

The  changing  of  the  motor  connections  at  the  end  of  the 
switch  operation  is  effected  by  the  mechanical  shifting  of  the 
contact  block  in  the  pole  changer  (Figs.  42  and  46).  In 
addition  to  being  mechanically  operated,  this  contact  block  is 
under  the  control  of  two  sets  of  solenoid  magnets,  so  that 
should  the  switch  fail  to  complete  its  movement  the  controlling 
lever  may  be  shifted,  and,  through  the  energizing  of  one 
set  of  the  magnets,  cause  the  pole  changer  to  set  up  the  circuit 
for  the  operation  of  the  switch  in  the  opposite  direction. 
This  places  the  mechanism  so  under  the  control  of  the  lever- 
man  that  should  the  switch  points  be  blocked  with  snow,  ice, 
etc.,  the  points  may  be  worked  back  and  forth,  frequently 
dislodging  the  obstruction,  thereby  permitting  the  desired 
movement  of  the  switch  to  be  completed. 


ELECTRIC    INTERLOCKING    HANDBOOK 


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indication  magnet  with  the  indication  magnet  armature  resting 
on  its  poles,  some  distance  from  the  poles  of  the  indication 
magnet.  The  safety  magnet  coils  are  so  connected  in  the 
operating  circuit  that  the  whole  operating  current  flows 
through  them,  hence  any  current  flowing  through  the  indica- 
tion magnet,  due  to  a  cross  between  the  control  wires  of  the 
function,  cannot  exceed  the  current  through  the  safety  magnet. 
The  winding  of  the  safety  magnet  is  proportioned  so  that  in 
conjunction  with  the  above  two  features,  the  indication  mag- 
net armature  cannot  be  lifted  by  current  resulting  from  a 
cross  as  stated  above. 


FIG.  40. 


MODEL  2  SWITCH  MACHINE.     BUFFALO  CREEK  INTER- 
LOCKING PLANT,  L.  S.  &  M.  S.  R'Y 


From  the  time  when  the  lever  is  moved  to  the  new  operating 
position  until  the  movement  of  the  switch  machine  is  com- 
pleted, the  indication  selector  further  insures  against  the  pos- 
sible receipt  of  any  improper  indication,  being  so  connected 
that  the  operating  current  will  attract  its  armature  and  close 
the  contact  for  the  reverse  indication  only  when  the  lever  is 
moved  reverse,  and  the  contact  for  the  normal  indication 
when  the  lever  is  moved  normal.  It  should  be  noted  that 
both  the  indication  selector  and  safety  magnet  coils  are  con- 
nected in  series  with  the  control  circuit,  therefore  if  the  cir- 
cuit through  them  is  not  intact,  operation  of  the  function  will 
be  prevented. 

When  the  motor  operating  circuit  is  opened  by  the  action 
of  the  pole  changer,  after  the  switch  has  been  locked  in  posi- 


ELECTRIC   INTERLOCKING  HANDBOOK 


63 


tion,  current  ceases  to  flow  through  the  safety  magnet.  There- 
fore the  armature  of  the  indication  magnet  is  no  longer  held 
down,  this  permitting  the  indication  to  be  effected  upon 
receipt  of  the  dynamic  current  generated  by  the  motor. 

The  mechanism  is  now  at  rest  protected  against  any  unau- 
thorized movement  in  the  same  manner  as  before  the  con- 
trolling lever  was  reversed. 

Owing  to  the  design  of  the  operating  circuits,  the  magnetic 


FIG.  41.     MODEL  2  SWITCH  MACHINE.     CLINTON  STREET  INTERLOCKING 

PLANT,  CHICAGO  TERMINAL,  C.  &  N.  W.  R'Y 

Spring   attachment   shown   is   furnished  with    Model   2  switch  machine 
when  detector  bar  is  not  installed. 

control  of  the  pole  changer  prevents  the  switch  from  being 
moved  by  hand  from  the  position  occupied,  except  through 
breaking  the  operating  circuits  by  some  such  means  as  re- 
moving the  motor  brushes.  If  this  is  done  and  the  machine 
moved  to  a  position  not  corresponding  with  that  of  its  con- 
trolling lever,  upon  the  replacement  of  the  brushes,  the  switch 
will  immediately  assume  its  proper  position.  Manipulation 
of  the  pole  changer  by  hand  will  not  cause  movement  of  the 
switch  out  of  correspondence  with  its  lever. 


64 


GENERAL  RAILWAY   SIGNAL  COMPANY 


MODEL  2  SWITCH  MACHINE 

The  Model  2  switch  machine,  illustrated  by  Fig.  43,  con- 
sists of  the  motor,  gearing,  lock  movement  and  the  pole  changer 
with  its  actuating  movement.  The  gear  frame  and  locking 
movement  are  securely  bolted  to  a  tie  plate  as  shown,  to 
which  plate  the  stock  rails  are  also  securely  attached,  thus 
rigidly  maintaining  all  parts  of  the  switch  machine  in  their 
proper  relation  to  each  other  and  to  the  rail. 

Movement  is  transmitted  to  the  various  switch  parts  by  the 
motor  through  a  train  of  spur  gears. 


FIG.  42.     POLE  CHANGER  FOR  MODEL  2  SWITCH  MACHINE 

The  locking  plunger  I  and  detector  bar  are  actuated  through 
the  lock  crank  H  and  the  driving  rod  G,  this  latter  being 
directly  connected  to  the  stud  F  on  the  main  gear  D1.  It  will 
be  seen  that  a  train  occupying  the  track,  in  preventing  the 
initial  movement  of  the  detector  bar,  would  make  impossible 
the  withdrawal  of  the  lock  plunger  from  the  throw  and  lock 
rods,  and  therefore  prevent  any  movement  of  the  switch 
points. 

The  switch  points  are  thrown  by  the  rod  J  and  the  cam 
crank  E  due  to  the  stud  F  on  the  main  gear  engaging  with  the 
cam  crank. 

The  operation  of  the  pole  changer  B  is  effected  through  the 
medium  of  the  pole  changer  movement  L  by  the  last  one- 
eighth  inch  movement  of  the  lock  plunger  I  after  it  has  passed 
through  the  lock  rod  K  (Fig.  146). 


ELECTRIC    INTERLOCKING   HANDBOOK 


65 


M  N        0 


DETECTOR     BAR 
CONNECTION 


FIG.  43.     MODEL  2  SWITCH  MACHINE 


Motor 

Pole  Changer 
Friction  Clutch 
Main  Gear 
Intermediate  Gear 
Cam  Crank 
Stud  on  Main  Gear 
Driving  Rod 


H  Lock  Crank 

I  Lock  Plunger 

J  Throw  Rod 

K  Lock  Rod 

L  Pole  Changer  Movement 

M  Pole  Changer  Connecting  Rod 

JV  Detector  Bar  Driving  Link 

O  Pin 


66 


GENERAL  RAILWAY   SIGNAL  COMPANY 


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ELECTRIC   INTERLOCKING   HANDBOOK  67 


The  design  of  the  mechanism  is  such  as  to  allow  the  switch 
motor  A,  due  to  its  acquired  momentum,  to  continue  its  rota- 
tion for  the  generation  of  the  indication,  which  checks  the 
speed  of  the  motor  and  brings  it  to  rest  without  shock. 

A  friction  clutch  C  is  introduced  into  the  connection  between 
the  switch  motor  and  the  main  gear  to  relieve  the  switch 
mechanism  from  any  injurious  strain  should  it  suddenly  be 
brought  to  stop  by  an  obstruction  in  the  switch  points. 

MODEL  4  SWITCH  MACHINE 

The  Model  4  switch  machine  shown  in  Fig.  44,  is  designed 
with  all  operating  parts  within  one  case,  and  is  especially 
adapted  for  installation  where  clearances  are  limited.  The 


FIG.  45.     MODEL  4  SWITCH  MACHINE.     NOBLE  STREET  INTERLOCKING 
PLANT,  CHICAGO  TERMINAL,  C.  &  N.  W.  R'r 

case,  which  affords  complete  protection  against  the  weather, 
provides  a  base  plate  for  the  mechanism,  being  bolted  through 
the  tie  plate  to  the  head  block  and  the  next  tie  back  (Fig.  149). 
The  operating  parts  consist  of  the  motor  A,  a  train  of  spur 
gears,  the  main  or  cam  gear  D,  the  pole  changer  M,  the  throw 
rod  J  and  locking  bar  F. 

The  motor  through  the  medium  of  the  train  of  gears  drives 
the  cam  gear,  from  which  gear  the  various  parts  of  the  switch 
machine  are  operated. 

The  intermittent  movement  of  the  locking  bar  and  detector 
bar  is  accomplished  by  the  engagement  of  rollers  on  the  locking 
bar  with  the  cam  slot  on  the  upper  side  of  the  main  gear. 
Staggered  locking  is  provided  by  the  arrangement  of  the  dogs 
on  the  locking  bar,  these  dogs  being  placed  so  that  after  one 
dog  has  been  withdrawn  to  release  the  lock  rod,  the  switch 
points  must  be  moved  to  the  opposite  position  before  the  other 
dog  can  enter  its  slot  in  the  lock  rod.  The  throw  rod  is  locked 


68 


GENERAL  RAILWAY  SIGNAL  COMPANY 


in  both  extreme  positions  of  the  switch  by  a  bolt  operated 
from  the  cam  movement. 

The  switch  points  are  thrown  at  the  proper  time  by  a  roller 
on  the  lower  side  of  the  main  gear  engaging  a  jaw  in  the 
throw  rod. 

The  principles  of  the  pole  changer  movement  are  essen- 
tially the  same  as  in  the  Model  2  switch  machine,  although  the 
mechanical  method  of  effecting  this  action  is  accomplished 
through  the  main  gear  movement  and  locking  bar,  instead  of 


FIG.  46.     POLE  CHANGER  FOB  MODEL  4  SWITCH  MACHINE 
Tripper  arm  N  shown  at  the  top  of  its  vertical  movement. 


through  the  pole  changer  movement  and  locking  plunger  as  in 
the  Model  2.  Contact  blocks  Si  and  S2  are  operated  from  tripper 
arm  N  which  engages  at  the  proper  time  with  a  cam  either  on  the 
or  lower  surface  of  the  main  gear  D,  depending 


upper 

direction  of  travel  of  the  mechanism. 


on  the 

The  tripper  arm  is 
placed  in  a  position  to  engage  with  the  proper  cam  only  after 
the  switch  has  been  locked  in  position  at  the  end  of  its  move- 
ment. This  is  accomplished  through  the  medium  of  cranks 
Tj  and  T2,  a  roller  U  on  the  latter  working  in  a  cam  slot  on  the 
locking  rod  P4.  The  contact  arm  V  (which  corresponds  with 
the  commutator  T  on  the  Model  2  pole  changer,  Fig.  42)  is 
operated  by  this  same  crank  movement. 


ELECTRIC   INTERLOCKING   HANDBOOK 


69 


The  cam  gear  is  designed  to  permit  a  free  run  of  the  motor 
at  the  end  of  the  operation  of  the  mechanism  for  the  purpose 
of  generating  a  strong  and  positive  indication  current. 

A  friction  clutch,  designed  with  large  surfaces  and  lined  with 
fibre,  is  provided  to  protect  the  mechanism  from  shock,  should 
its  movements  be  obstructed. 

A  switch  circuit  controller  can  be  furnished  if  desired, 
located  within  the  mechanism  case  at  the  point  indicated  by 
letter  O.  The  operating  part  consists  of  a  frame  carrying 
contact  fingers  and  a  cylindrical  commutator  W  upon  which 
are  mounted  contact  segments.  As  the  switch  is  unlocked,  a 
disengaging  arm  X  with  roller  Y  working  in  a  cam  slot  on  the 
locking  bar  Flf  lowers  the  commutator  out  of  engagement  with 
the  contact  springs.  During  the  movement  of  the  switch 
points,  the  commutator  is  rotated  on  its  axis  through  motion 


FIG.  47.     SWITCH  CIRCUIT  CONTROLLER  FOR  MODEL  4  SWITCH  MACHINE 

transmitted  from  the  switch  points  by  means  of  a  crank  con- 
nection, a  sector  (not  shown)  and  pinions  Zt  and  Z2.  After 
the  points  are  locked  in  position  the  commutator  is  raised  into 
engagement  with  the  contact  fingers  by  the  engaging  arm  and 
cam  slot  movement.  It  will  be  seen  that  this  control  insures 
the  switch  points  are  in  position  and  locked  in  position  before 
the  switch  circuit  controller  can  be  closed.  The  maximum 
capacity  of  the  controller  is  ten  independent  circuits,  the  con- 
tacts being  adjustable  in  pairs  to  close  as  desired  at  the 
normal  or  reverse  positions  of  the  switch. 

The  switch  mechanism  can  be  used  right  or  left  handed 
without  change,  as  the  lock  and  throw  rods  may  be  connected 
from  either  side.  A  double  locking  cage  is  furnished  when  the 
machine  is  to  operate  a  double  slip  switch  or  movable  point 
frog,  thus  avoiding  the  necessity  of  using  a  plunger  lock  with  its 
special  connections  otherwise  required  for  the  second  lock  rod. 

All  parts  are  assembled  in  the  factory  and  tested  before 
shipment  under  conditions  approximating  as  nearly  as  possible 
the  service  to  be  given  the  machine  after  installation. 


MOTOR  DRIVEN  SIGNAL  MECHANISMS 

MOTOR  driven  signals  in  the  G.  R.  S.  system  of  electric 
interlocking  are  operated  by  mechanisms  in  which  a 
series  wound  motor  is  directly  connected  to  the  sema- 
phore shaft  through  the  medium  of  low  reduction  gearing.  No 
dash-pot  or  electro-mechanical  slot  is  required  for  this  type  of 
signal.  The  mechanism  is  applicable  for  use  as  a  high  or 
dwarf  signal. 

The  mechanisms  furnished  are  of  two  types : 

First,  the  non-automatic,  which  is  entirely  under  the  control 
of  a  lever  in  the  interlocking  machine.  Generally  speaking, 
this  type  is  furnished  for  dwarf  signals,  and  for  such  high 
signals  as  will  at  no  time  require  track  circuit  control. 

Second,  the  semi-automatic,  which  is  operated  under  the 
joint  control  of  a  lever  in  the  interlocking  machine  and  the 
track  circuits  in  such  sections  of  track  as  are  governed  by  the 
signal  arm.  The  semi-automatic  mechanism  is  also  furnished 
for  non-automatic  high  signals  when  there  is  a  possibility  of 
the  signal  arm  being  controlled  by  track  circuits  at  some  future 
time,  or  in  case  it  is  desired  to  have  uniformity  in  the  type  of 
mechanism  throughout  the  installation. 

Either  of  the  above  types  can  be  adapted  for  operation  in 
two  or  three  positions,  upper  or  lower  quadrant,  and  to  give 
right  or  left  hand  indications  as  desired. 

In  the  two  position  non-automatic  signals,  but  one  wire 
besides  the  main  common  is  required  for  its  control,  this  wire 
being  used  both  for  operating  and  indicating  purposes.  When 
the  signal  is  to  operate  in  three  positions  an  additional  control 
wire  is  required.  In  the  case  of  semi-automatic  control,  an 
additional  wire  may  or  may  not  be  required,  depending  entirely 
upon  the  arrangement  of  the  track  circuits  in  the  route  governed 
by  the  signal  arm. 

NON-AUTOMATIC   SIGNAL  CONTROL 

The  following  description  of  the  signal  operation  is  based 
on  the  circuit  shown  in  Fig.  48  which  is  for  the  control  of  the 
two  position  non-automatic  signal  mechanism. 

Upon  reversal  of  the  controlling  lever  current  is  taken 
from  the  positive  buss  bar  through  the  lever  contacts,  the 
control  wire,  the  operating  field  and  armature  of  the  signal 
motor,  and  thence  to  common  through  the  various  switch 
circuit  controllers  as  required.  This  causes  the  movement  of 
the  blade  from  stop  to  the  proceed  position,  upon  the  com- 
pletion of  which  movement  circuit  breaker  contact  B  opens 
and  A  closes,  this  connecting  the  holding  field  of  the  motor  in 
series  with  the  operating  field  and  armature.  The  design  of 
the  pole  pieces  on  which  the  holding  field  windings  are  mounted, 
is  such  that  the  magnetic  flux,  thrown  across  the  air  gap 
between  the  motor  armature  and  the  pole  pieces,  magnetically 
locks  the  armature  against  rotation  and  thereby  retains  the 


ELECTRIC   INTERLOCKING   HANDBOOK 


71 


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72  GENERAL  RAILWAY   SIGNAL  COMPANY 


mechanism  and  brings  it  to  rest  without  shock  to  any  of  its 
parts. 

In  the  case  of  the  three  position  signal,  operation  from  the 
zero  degree  position  to  the  forty-five  degree  position  is  the 
same  as  described  above.  Operation  from  this  point  on  to  the 
ninety  degree  position  is  ordinarily  dependent  upon  the  signal 
in  advance,  it  being  necessary  however  that  the  controlling 
lever  be  reversed  before  movement  of  the  mechanism  can  take 
place.  The  mechanism  is  held  in  its  ninety  degree  position 
through  the  medium  of  the  holding  fields  in  the  same  manner  as 
in  the  forty-five  degree  position.  When  the  signal  arm  is  re- 
turning from  the  ninety  degree  position  and  is  to  be  held  at 
the  forty-five  degree  position,  its  movement  is  arrested  at  that 
point  by  short  circuiting  a  "  snubbing  "  winding  on  the  motor 
(winding  and  contact  not  shown  in  Fig.  48),  which  causes  a 
momentary  current  to  flow  in  this  winding,  thereby  bringing 
the  mechanism  parts  to  rest.  The  semaphore  arm  is  retained 
in  this  position  by  current  flowing  through  the  retaining  fields 
of  the  motor,  as  previously  explained. 

SEMI-AUTOMATIC  SIGNAL  CONTROL 

When  it  is  desired  to  have  the  signal  controlled  semi-auto- 
matically,  the  operation  differs  from  that  described  above 
in  that  the  first  forty  degree  movement  of  the  mechanism 
from  the  normal  position  does  not  affect  the  position  of  the 
signal  arm,  but  puts  under  tension  a  set  of  coil  springs  which 
are  strong  enough  to  rotate  the  motor  on  the  return  movement 
with  sufficient  speed  to  generate  the  current  for  energizing 
the  indication  magnet  on  the  lever.  This  preliminary  move- 
ment of  the  mechanism  is  always  under  the  control  of  the 
operating  lever  irrespective  of  whether  the  track  circuit  is 
occupied  or  not,  the  receipt  of  the  indication  therefore  ^ot 
requiring  the  restoration  of  the  lever  to  the  normal  position 
simultaneous  with  the  entrance  of  a  train  into  the  controlling 
track  section.  Any  movement  of  the  mechanism  beyond  this 
point,  however,  is  dependent  upon  the  track  circuit  being 
unoccupied. 

Referring  to  the  circuit  for  the  two  position  semi-auto- 
matic signal  as  shown  in  Fig.  49,  it  will  be  seen  that  upon 
reversal  of  the  controlling  lever  current  is  taken  from  the 
positive  buss  bar  through  the  lever  contacts,  the  control 
wire,  the  signal  motor  operating  field  and  armature  and  thence 
to  common.  This  causes  the  operation  of  the  mechanism 
through  its  preliminary  forty  degree  movement  to  the 
zero  degree  position,  at  which  point  the  mechanism  will 
be  held  against  the  tension  of  the  coil  springs,  in  the  event 
of  the  track  circuit  being  occupied;  this  is  accomplished  by 
circuit  breaker  contact  Bx  opening  and  A!  closing  which 
connects  the  holding  fields  in  series  with  the  operating  fields 
and  armature  of  the  signal  motor.  Should  the  track  circuit 
be  unoccupied,  the  mechanism  will  not  stop  at  this  point  but 


ELECTRIC   INTERLOCKING   HANDBOOK 


73 


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GENERAL  RAILWAY  SIGNAL  COMPANY 


time  as  its  lever  may  be  reversed ;  the  control  is  so  arranged  that 
a  second  clearing  of  the  signal  arm  can  be  secured  only  after  the 
mechanism  has  been  returned  to  its  minus  forty  (—40)  degree 
position.  When  the  lever  is  restored  normal,  energy  is  cut  off 
from  the  motor  and  the  mechanism,  due  to  the  tension  of 
the  coil  springs,  is  driven  to  its  minus  forty  (  —  40)  degree 
position;  just  before  reaching  this  position  circuit  breaker 


FIG.  50.     MODEL  2A  DWARF  SIGNAL.     ELECTRIC  DIVISION, 
N.  Y.  C.  &  H.  R.  R.  R. 

contact  B!  closes,  thus  connecting  the  motor  armature  and 
operating  field  in  their  original  closed  circuit  in  which  is 
included  the  indication  magnet.  Due  to  the  momentum  of 
the  motor  armature  acquired  during  this  movement,  the  motor 
(now  a  generator)  builds  up  the  momentary  dynamic  current 
necessary  to  energize  the  indication  magnet  and  release  the 
lever,  thereby  permitting  it  to  be  restored  to  its  full  normal 
position. 


Should  the  controlling  lever  be  placed  normal  before  the 
the  controlling  track  section,  the  signal 


entrance  of  a  train  into 


ELECTRIC  INTERLOCKING   HANDBOOK 


75 


arm    and    mechanism    returns    to  the  zero 
position,   and  the  mechanism   continues  its 


degree   or   stop 
rotation  to  the 


minus  forty  (—40)  degree  position  due  to  the  action  of  the 
indication  springs;  when  within  a  few  degrees  of  the  end  oHts 
travel,  the  dynamic  indication  for  the  release  of  the  controlling 
lever  is  generated  as  described  above. 


FIG. 


DEL  2A  DWARF  SIGNALS. 
C.  &  N.  W.  R'Y 


CHICAGO  TERMINAL, 


It  will  be  seen  that  the  operation  of  the  signal  mechanism 
proper,  from  the  time  the  signal  blade  begins  its  movement 
toward  the  proceed  position  until  its  return  to  the  stop  posi- 
tion, is  the  same  as  that  of  the  non-automatic  signal,  the 
indication  springs  being  in  no  way  depended  upon  to  bring  the 
signal  arm  to  the  stop  position.  This  same  statement  applies 
also  to  three  position  operation  of  the  semi-automatic 
mechanism. 


76 


GENERAL   RAILWAY  SIGNAL  COMPANY 


a  -o^gfcg 

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ELECTRIC   INTERLOCKING   HANDBOOK  77 

MODEL  2A  NON-AUTOMATIC  SIGNAL  MECHANISM 

The  non-automatic  signal  mechanism  (Fig.  52)  consists 
essentially  of  three  main  parts,  the  motor,  a  train  of  gears 
and  the  circuit  breaker.  These  are  all  housed  in  a  weather 
proof  case,  which  is  provided  with  doors  to  give  convenient 
access  to  all  parts. 

When  the  mechanism  is  used  for  the  operation  of  high 
signals,  it  is  fastened  to  a  clamp  bearing  (Fig.  54)  which 
carries  the  semaphore  shaft  S,  the  design  of  this  bearing 
permitting  the  mechanism  to  be  supported  at  any  desired 
height  on  the  signal  mast  and  at  any  angle  to  the  track.  The 
bearing  is  equipped  with  a  spring  stop  P,  which  besides  acting 
as  a  buffer  permits  the  close  adjustment  of  the  signal  blade  in 
its  stop  position.  A  universal  coupling  L1;  L,,  L3  introduced 
between  the  driving  shaft  J  and  semaphore  shaft  S,  lends 
itself  to  a  simple  means  of  locking  the  signal  arm  in  the  stop 
position  in  such  a  way  as  to  prevent  improper  operation  of 
the  signal  by  any  outside  agency. 

When  the  signal  mechanism  is  to  be  used  for  the  operation 
of  a  dwarf  signal,  it  is  bolted  to  a  stand  (Fig.  55)  carrying 
the  spectacle  shaft  T  and  provided  with  springs  Ut  and  U2 
which  are  for  the  purpose  of  giving  sufficient  returning  torque 
to  the  dwarf  signal  arm  to  cause  it  to  assume  the  stop  position 
when  the  current  holding  it  at  proceed  is  cut  off.  This  is 
necessary  since  the  dwarf  signal  arm  cannot  be  readily  designed 
to  have  sufficient  weight  so  that  gravity  can  be  depended  upon 
for  returning  it  to  the  stop  position.  The  complete  dwarf 
mechanism  takes  up  but  little  room  which  permits  it  to  be 
installed  where  clearances  are  limited,  as  is  illustrated  by 
Fig.  202. 

The  motor  A  used  in  the  signal  mechanism  is  of  the  four 
pole  type,  two  of  these  poles  being  modified  in  such  a  man- 
ner as  to  permit  the  motor  armature  to  constitute  the  means  for 
holding  the  signal  arm  in  the  proceed  positions.  This  modified 
design  consists  of  serrating  the  surfaces  of  these  two  poles, 
so  that  when  the  holding  field  windings  are  energized,  a  dense 
magnetic  flux  will  flow  across  the  air  gap  between  the  pole 
pieces  and  the  motor  armature  in  such  a  manner  as  to  pre- 
vent rotation  of  the  armature,  and,  consequently,  movement 
of  the  signal  blade.  Owing  to  the  high  resistance  of  these 
windings  the  amount  of  current  used  for  the  purpose  is  re- 
duced to  a  minimum.  The  ''snubbing"  winding  previously 
referred  to  is  entirely  independent  from  the  operating  wind- 
ings of  the  motor,  its  function  being  to  check  the  speed  of  the 
motor  when  it  is  desired  to  hold  the  signal  arm  in  the  forty- 
five  degree  position. 

A  friction  clutch  is  introduced  between  the  motor  A  and 
its  driving  pinion  C  to  insure  that  no  undue  strain  whatsoever 
will  be  transmitted  to  the  mechanism  gearing. 

The  gearing  is  designed  with  heavy  teeth  and  large  clear- 
ances as  shown  by  Fig.  53,  this  latter  insuring  that  the 


78 


GENERAL  RAILWAY  SIGNAL  COMPANY 


mechanisms  will  run  freely  in  either  direction  and  that  no 
ordinary  obstructions  such  as  dirt,  cinders,  waste,  etc.,  will 
interfere  with  its  movement;  only  five  foot  pounds  at  the 
semaphore  shaft  are  required  to  run  the  mechanism  back  to 
its  normal  position. 


FIG.  53.     DIAGRAM  ILLUSTRATING  GEARING  CLEARANCE 

IN  MODEL  2A  SIGNAL  MECHANISM 

Scale,  full  size. 

The  circuit  breaker  B  is  a  complete  unit  operated  from  the 
main  driving  shaft  J  by  means  of  the  segmental  gears  Kt 
and  K2.  It  consists  of  a  frame  carrying  contact  fingers  and 
a  revolving  commutator  on  which  are  mounted  contact  seg- 
ments as  required.  The  circuit  breaker  has  a  maximum 


ELECTRIC   INTERLOCKING   HANDBOOK 


79 


capacity  of  fourteen  circuits,  such  contacts  as  are  used  to 
control  operating  and  indicating  circuits  being  arranged  to 
be  quick  acting,  "snapping"  over  from  one  position  to  the 
other  at  the  proper  predetermined  time.  Each  contact  finger 
is  provided  with  convenient  means  of  adjustment,  and  by 
means  of  a  locking  finger  is  positively  protected  again  acci- 
dental displacement. 


V --'  " -* 

FIG.  54.     CLAMP  BEARING  FOR  MOUNTING  MODEL  2A  SIGNAL  MECHAN- 
ISM ON  SIGNAL  MAST 


FIG.  55.     DWARF  BEARING  FOR  MODEL  2A  SIGNAL  MECHANISM 


80 


GENERAL  RAILWAY  SIGNAL  COMPANY 


fe 


ELECTRIC   INTERLOCKING   HANDBOOK  81 


MODEL  2A  SEMI-AUTOMATIC  SIGNAL  MECHANISM 

The  semi-automatic  signal  mechanism  (Fig.  56)  consists 
essentially,  as  does  the  non-automatic  mechanism,  of  a  motor, 
a  train  of  gears  and  circuit  breaker,  with  the  addition,  however, 
of  the  spring  attachment  which  is  used  to  produce  rotation  of 
the  motor  armature  for  indication  purposes  after  the  signal 
arm  has  reached  the  stop  position.  These  parts  are  enclosed 
in  a  weather  proof  case  similar  in  construction  to  that  used  for 


Fia.  57.     MODEL  2 A  SEMI-AUTOMATIC  SIGNAL 

the  non-automatic  signal,  the  design  permitting  the  mechanism 
to  be  fastened  to  a  clamp  bearing  for  mounting  on  high  signal 
masts  or  used  in  connection  with  a  stand  for  operation  as  a 
dwarf. 

The  motor,  train  of  gears  and  circuit  breaker  are  essentially 
the  same  as  those  described  above,  it  being  therefore  only 
necessary  to  touch  upon  the  design  of  the  indication  spring 
attachment  and  the  universal  coupling,  these  being  the  only 
points  in  which  this  signal  is  radically  different  from  the  non- 
automatic  previously  described. 

The  initial  free  movement  of  the  mechanism  is  accomplished 
by  having  one  shoulder  of  the  coupling  L2  so  cut  away  that 
a  forty  degree  rotation  of  the  driving  shaft  J  is  necessary 
before  it  will  engage  with  the  semaphore  shaft  S,  this  movement 


82 


GENERAL  RAILWAY   SIGNAL  COMPANY 


as  previously  mentioned  putting  under  tension  the  pair  of  coil 
springs  Na  and  N?. 

Fig.  58  shows  diagramatically  this  spring  attachment  and  the 
manner  in  which  the  springs  N\  and  N2  are  put  under  tension ; 
it  will  be  noted  that  the  two  coil  springs  are  connected  to  the 
driving  shaft  J  by  means  of  an  equalizer  O  and  a  curved  link 


Lost  motion  betrroen 
Sector  H  and  Spectacle 


Sector  operated  by  motor 
through  train  of  gears. 


FIG.  58.     DIAGRAM   SHOWING  OPERATION  OF  SPRING  ATTACHMENT  USED 
IN  MODEL  2A  SEMI-AUTOMATIC  SIGNAL  MECHANISM 

M,  one  end  of  which  is  fastened  to  the  main  sector  H  on 
the  driving  shaft  J.  As  is  clearly  illustrated  by  the  various 
positions  of  the  device  the  design  is  such  that  the  springs  do 
not  exert  any  torque  on  the  mechanism  after  the  blade  has 
moved  a  few  degrees  from  the  stop  position;  therefore  it  is 
plain  that  the  springs  are  in  no  way  depended  upon  for  the 
restoration  of  the  blade  to  the  normal  position. 


SOLENOID   DWARF  SIGNAL  MECHANISMS 

SOLENOID  dwarf  signals  used  in  the  G.  R.  S.  system  are 
designed  to  operate   in   two  positions,  upper   or   lower 
quadrant,  with  a  forty-five,  sixty  or  ninety  degree  travel 
of  the  arm.      Two  sets  of  magnet    windings   are   provided, 
which  consist  of  operating  coils  of  low  resistance  and  holding 
coils   of    high   resistance.      The    movement    of    the    solenoid 
magnet  plungers  is   transmitted  by  means  of  suitable  con- 
nection to  the  dwarf  spectacle. 


FIG.  59.     MODEL  2  SOLENOID  DWARF  SIGNAL 

DWARF  SIGNAL  CONTROL 

Each  of  these  mechanisms  requires  for  its  operation  a  con- 
trol wire,  and  since  it  is  impracticable  to  secure  a  dynamic 
indication  from  a  signal  of  the  solenoid  type,  an  additional 
wire  is  required  for  indication  purposes.  The  circuit  is  con- 
nected to  main  common  either  at  the  dwarf  location  or 
through  contacts  on  switch  circuit  controllers  when  required. 

Upon  reversal  of  the  controlling  lever  (Fig.  60),  current  is 
taken  from  the  positive  buss  bar  through  the  lever  contacts, 
the  control  wire,  and  the  solenoid  operating  coils  A!  and  Aa 
to  common.  This  causes  movement  of  the  signal  arm  from  the 
stop  to  the  proceed  position.  As  the  arm  reaches  the  pro- 
ceed position,  the  circuit  breaker  contact  C  opens,  which 
connects  the  high  resistance  holding  coils  Bx  and  B2  in  series 


84 


GENERAL  RAILWAY  SIGNAL  COMPANY 


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ELECTRIC   INTERLOCKING   HANDBOOK 


85 


which,  in  addition  to  supporting  the  mechanism,  is  designed 
to  carry  the  dwarf  spectacle  shaft.  A  hinged  cover  on  the 
top  of  the  case  gives  convenient  access  to  the  mechanism. 

The  movement  of  the  yoke  F  connecting  the  solenoid  plung- 
ers Ex  and  E2,  is  transmitted  through  the  medium  of  the  rack 
G  and  pinion  H  to  the  crank  J,  and  thence  by  means  of  the 
connecting  rod  (not  shown)  to  the  dwarf  spectacle  shaft. 

When  in  the  stop  position  the  signal  arm  cannot  be  moved 
by  any  outside  agency,  due  to  the  crank  J  being  "on  center" 
at  that  point. 


FIG.  61.     MODEL  2  SOLENOID  DWARF  SIGNAL  OPERATING 
MECHANISM 

Aj-^2    Operating'Coils  F  Yoke 

Bi-B2    Holding  Coils  G  Rack 

C             Operating  Contact  H  Pinion 

D            Indicating  Contact  J  Crank 
Ei-E,    Solenoid  Plungers 


The  circuits  for  the  control  of  the  mechanism  are  broken 
through  pairs  of  springs  which  make  contact  at  the  proper 
time  with  metal  pieces,  fastened  to  a  commutator  mounted 
upon  the  same  shaft  as  the  pinion  H.  The  operating  contact 
C  is  designed  to  hold  its  circuit  closed  throughout  the  move- 
ment until  the  blade  has  assumed  the  proceed  position.  The 
indicating  contact  D  is  closed  only  when  the  blade  is  in  the 
stop  position. 


86  GENERAL  RAILWAY  SIGNAL  COMPANY 


MODEL  3  DWARF  SIGNAL  MECHANISM 

The  Model  3  dwarf  signal  mechanism  (Fig.  63)  consists,  of 
the  solenoid  magnets  and  an  operating  rod  which  is  directly 
connected  to  the  dwarf  spectacle  shaft.  This  mechanism  is 
mounted  in  a  case  which  is  designed  to  carry  the  dwarf  spec- 
tacle shaft  and  is  provided  with  a  sliding  cover  to  permit 
ready  access  to  the  operating  parts. 

The  operation  of  the  mechanism  is  similar  in  principle  to 
that  of  the  Model  2  dwarf  except  that  the  movement  of  the 


FIG.  62.     MODEL  3  SOLENOID  DWARF  SIGNAL 

magnet  plungers  Et  and  E2  is  transmitted  directly  to  the 
spectacle  shaft  through  the  operating  rod  G,  a  roller  H  on  the 
operating  rod  working  in  an  escapement  crank  (not  shown) 
on  the  semaphore  shaft.  The  design  is  such  that  when  the 
signal  is  in  its  normal  position,  the  arm  is  locked  against 
movement  from  the  outside. 

The  overall  dimensions  of  the  signal  are  such  as  to  allow  its 
location  where  the  available  clearances  will  not  permit  the 
use  of  the  Model  2  dwarf  signal. 

The  circuit  breaker  contacts  consist  of  pairs  of  springs 
which  are  bridged  by  contact  rollers,  actuated  by  the  oper- 
ating rod  G.  In  the  case  of  the  indicating  contact  D  and 
spare  contact  J,  the  contact  rollers  are  fastened  to  and 
move  with  the  operating  rod,  the  design  causing  the  contacts 


ELECTRIC   INTERLOCKING   HANDBOOK 


87 


FIG.  63.     MODEL  3  SOLENOID  DWARF  SIGNAL  OPERATING 
MECHANISM 

F  Yoke 

G  Operating  Rod 

H  Roller 

J  Spare  Contact 


Operating  Coils 
Holding  Coils 
Operating  Contact 
Indicating  Contact 
Solenoid  Plungers 


to  open  with  the  first  movement  of  the  arm  towards  the  pro- 
ceed position.  The  roller  for  the  operating  contact  C  is  car- 
ried by  an  arm,  which  is  raised  by  engagement  with  a  collar 
on  the  operating  rod,  when  the  dwarf  spectacle  has  assumed 
the  proceed  position. 


GENERAL  RAILWAY   SIGNAL   COMPANY 


I 


CROSS  PROTECTION  APPARATUS 
PRINCIPLES  OF  G.  R.  S.  CROSS  PROTECTION 

THE  G.  R.  S.  cross  protection  system  prevents  the  unau- 
thorized movement  of  any  switch,  signal,  or  other  func- 
tion, in  the  event  of  current  being  improperly  applied  to 
its  circuit,  by  the  cutting  off  all  energy  from  the  function. 

As  briefly  outlined  in  the  pages  on  the  "G.  R.  S.  Electric 
Interlocking  System,"  it  has  been  seen  that  all  functions 
while  at  rest  are  normally  on  a  closed  circuit  of  low  resistance ; 
that  inserted  in  each  of  these  circuits  and  located  on  the  ter- 
minal board  of  the  interlocking  machine,  is  a  polarized  relay 
of  very  low  resistance  connected  in  such  a  manner  that  all 
currents,  caused  to  flow  through  the  circuit  by  the  manipu- 


CIRCUIT  BREAKER  A 


FIG.  65.     SIMPLIFIED  CIRCUIT  SHOWING  THE  PRINCIPLES  OF  THE 

G.  R.  S.  CROSS  PROTECTION  SYSTEM 

All  functions  when  at  rest  are  on  closed  circuit  as  shown  by  function  C. 
All  normal  currents  will  flow  through  the  polarized  relay  B  in  the  direction 
indicated  by  the  heavy  arrows,  but  all  currents  due  to  a  cross  in  the  oppo- 
site direction  as  indicated  by  the  dotted  arrows.  Hence  current  supplied 
through  a  cross  X  will  open  polarized  relay  B,  which  will  cause  circuit 
breaker  A  to  open  and  thus  cut  current  off  the  system. 


lation  of  the  lever,  must  pass  through  the  relay  in  a  direction 
to  maintain  its  contact  closed,  while  all  currents  which  may 
be  applied  through  any  other  channel  must  pass  through  this 
relay  in  a  direction  to  cause  it  to  open  its  contact;  and  that 
this  operation  breaks  the  control  circuit  of  the  cross  protec- 
tion circuit  breaker,  causing  it  to  open  and  cut  power  off  that 
section  of  the  system  affected,  thereby  preventing  the  unauthor- 
ized movement  of  the  function.  The  principles  involved  will  be 
made  evident  by  reference  to  Fig.  65,  from  which  circuit  has 
been  eliminated  all  detail  connections,  contacts,  etc.,  only 
such  parts  being  shown  as  are  essential  to  the  explanation. 

In  Fig.  64  there  is  shown  in  full  circuit  detail  all  apparatus 
and  contacts  pertaining  to  a  switch  function,  a  signal  function, 


90 


GENERAL   RAILWAY   SIGNAL   COMPANY 


ELECTRIC   INTERLOCKING   HANDBOOK  91 

and  the  system  of  cross  protection.  By  tracing  out  these 
circuits  it  will  be  found  that  the  circuit  conditions  as  shown 
in  Fig.  65  exist  and  afford  the  protection  claimed. 

OPERATION  OP  THE  CROSS  PROTECTION  CIRCUIT  BREAKER 

The  circuit  breaker  construction  and  its  manipulation  are 
clearly  illustrated  by  Fig.  66,  the  position  in  Fig.  66C  cor- 
responding with  that  of  the  circuit  breaker  in  Fig.  64.  The 
various  parts  of  the  circuit  breaker  which  make  contact  with 
each  other  are  indicated  by  similar  letters. 

It  has  been  shown  that  current  applied  from  an  unauthor- 
ized source  to  the  circuit  of  a  function  at  rest,  causes  the 
polarized  relay  in  that  function's  circuit  to  open  its  contact 
and  interrupt  the  circuit  through  the  retaining  magnet  of  the 
cross  protection  circuit  breaker.  When  this  occurs  the  cir- 
cuit breaker  armature  is  released  and  the  Z  contacts  are 
opened,  the  armature  falling  to  such  a  position  (Fig.  66A) 
that  it  cannot  be  drawn  up  against  the  pole  pieces  by  the 
magnetic  pull  which  will  be  exerted  when  the  retaining  magnet 
is  again  energized  through  the  restoration  of  the  polarized 
relay  armature.  To  inform  the  leverman  that  the  circuit 
breaker  is  open,  a  red  lamp  is  lighted  by  the  closing  of  the  Y 
contacts. 

With  the  circuit  breaker  open  as  in  Fig.  66A,  the  positive 
and  negative  feeder  wires  between  the  battery  and  the  inter- 
locking system  are  opened  at  the  Z  contacts,  therefore  the 
cross  can  have  no  effect.  The  polarized  relay  which  had  its 
armature  reversed  will  identify  the  function  affected  and,  upon 
the  cause  of  the  trouble  being  removed,  the  armature  of  this 
polarized  relay  will  remain  in  its  normal  position,  when  re- 
placed by  the  operator.  This  will  cause  the  retaining  magnet 
of  the  cross  protection  circuit  breaker  to  be  energized,  and, 
by  raising  the  restoring  handle  to  the  position  shown  in  Fig. 
66B  the  circuit  breaker  armature  is  restored  to  its  operating 
position  where  it  will  be  retained  by  the  circuit  breaker  magnet. 
This  action  closes  the  Z  contacts,  but  at  the  same  time  opens 
the  X  contacts,  through  which  contacts  are  also  broken  the 
positive  and  negative  feeder  wires,  this  preventing  the  appli- 
cation of  current  to  all  functions  controlled  by  the  circuit 
breaker  until  the  restoring  handle  is  returned  to  its  normal 
position.  The  red  light  is  extinguished  when  the  circuit 
breaker  armature  is  restored. 

Figs.  24  and  25  illustrate  a  typical  operating  switchboard, 
one  view  showing  the  cross  protection  circuit  breaker  exposed 
and  the  other  with  its  coyer  in  place.  It  will  be  noted  that 
the  only  portion  of  the  circuit  breaker  which  is  accessible  to 
the  leverman  is  the  restoring  handle  projecting  from  the  slot 
at  the  bottom  of  the  cover.  A  shield  attached  to  this  handle 
closes  this  slot  when  the  handle  is  in  the  normal  position, 
thereby  protecting  the  internal  parts  against  manipulation  in 
any  way  except  by  means  of  the  restoring  handle.  As 


92  GENERAL  RAILWAY  SIGNAL  COMPANY 


explained  above,  so  long  as  the  handle  is  held  in  a  position  to 
interfere  with  the  release  of  the  contacts  normally  retained  by 
the  magnet  (Fig.  66B),  energy  is  withheld  from  all  functions 
under  the  control  of  the  circuit  breaker.  These  features  make 
the  cross  protection  system  fully  effective  at  all  times,  even 
though  force  of  circumstances  may  require  its  being  temporarily 
under  the  charge  of  unskilled  employees. 

When  it  is  desired  to  retain  such  signals  in  the  proceed 
position  as  may  be  occupying  that  position  when  the  circuit 
breaker  opens,  resistance  units  R  and  R!  (shown  dotted  in  Fig. 
64)  are  connected  so  as  to  bridge  the  X  and  Z  contacts,  these 
units  permitting  the  flow  of  an  amount  of  current  sufficient  to 
hold  a  limited  number  of  signals  at  proceed.  Their  resistance 
is  so  high,  however,  that  the  mechanism  requiring  the  least 


FIG.  67.     POLARIZED  RELAY 

current  for  its  operation  cannot  be  put  in  motion  if  energy 
should  be  applied  to  its  circuit  when  the  circuit  breaker  is  open. 
The  resistance  units  are  shown  in  position  on  the  operating 
switchboard  in  Fig.  24. 

THE  POLARIZED  RELAYS 

The  polarized  relay  inserted  in  the  indication  circuit  of 
each  of  the  operated  functions,  and  mounted  on  the  terminal 
board  of  the  interlocking  machine,  is  shown  in  Fig.  67.  The 
windings  are  so  designed  that  the  armature  of  the  relay  for 
a  switch,  signal,  etc.,  will  reverse  on  about  one-half  the  current 
required  to  just  move  that  function  of  the  same  type  which 
requires  the  least  current  for  its  operation.  From  this  it  will 
be  seen  that  the  windings  of  the  polarized  relays  used  with 
different  types  of  functions  have  different  resistances. 

On  the  switchboard  there  is  shown  in  Fig.  24  a  polarized 
relay  similar  to  those  mounted  on  the  interlocking  machine, 
the  position  of  this  relay  in  the  circuit  (Fig.  64)  being  indi- 
cated by  the  letter  "A."  This  relay  guards  against  crosses 


ELECTRIC   INTERLOCKING    HANDBOOK  93 


between  the  buss  bars  on  the  interlocking  machine,  such  as 
might  be  accidently  caused  by  the  maintainer's  tools  when 
he  is  working  about  the  machine.  From  the  position  of  the 
relay  in  the  circuit,  it  will  be  seen  that  any  current  reaching 
the  indication  buss  bar  through  such  a  cross  will  flow  in  the 
direction  opposite  to  that  of  the  indication  currents,  this 
causing  the  relay  to  reverse  its  contact  in  the  same  manner  as 
the  polarized  relays  previously  described.  Since  the  relay  on 
the  switchboard  is  common  to  all  circuits,  its  winding  is 
designed  to  render  it  much  less  sensitive  than  those  on  the 
interlocking  machine. 

SAFEGUARDS 

To  show  that  the  system  in  addition  to  being  extremely 
simple,  is  also  fully  safeguarded,  the  following  points  are 
mentioned : 

First  —  The  closed  circuit  principle  is  employed  for  all 
parts  of  the  cross  protection  system. 

Second  —  All  contacts  or  connections  depended  upon  for 
protection  against  crosses  are  also  used  in  operation  and, 
hence,  are  checked  as  to  their  integrity  every  time  a  complete 
operation  of  a  function  is  made. 

Third  —  The  polarized  relay  contact,  in  addition  to  opening 
on  a  reversed  direction  of  current,  will  also  open  upon  loss  of 
magnetism  in  the  permanent  magnet  of  the  relay. 

Fourth  —  An  open  circuit  in  the  polarized  relay  prevents 
indication. 

SECTIONALIZING  OF  PLANTS 

In  connection  with  a  comparatively  simple  track  layout,  it 
is  common  practice  to  install  only  one  cross  protection  circuit 
breaker,  which  prevents  the  movement  of  all  functions  during 
such  time  as  it  may  be  open.  At  busy  plants  having  a  large 
number  of  routes  which  can  be  used  simultaneously,  it  may  be 
considered  undesirable  to  have  the  whole  plant  affected  by 
derangement  at  a  single  point,  in  which  case  the  plant  may 
be  divided  into  sections,  the  functions  in  each  section  being 
controlled  through  separate  circuit  breakers.  This  ^  permits 
uninterrupted  operation  of  traffic  through  the  sections  not 
directly  affected. 

In  addition  to  the  cross  protection  circuit  breakers  required, 
it  is  necessary  to  install  switchboard  polarized  relays  and  also 
common  return  wires  for  each  section  in  the  interlocking  plant. 
The  positive  buss  bar  and  indication  buss  bar  must  be  divided 
to  correspond  with  the  sectional  division  of  the  functions.  It 
is  essential  that  there  be  no  connections  between  the  various 
buss  bars  or  the  common  return  wires,  except  where  they 
join  the  energy  mains  from  the  battery,  under  the  protection 
of  their  respective  cross  protection  circuit  breakers. 

There  may  be  certain  situations  where  conditions  will 
warrant  the  additional  expense  of  employing  individual  cross 
protection  circuit  breakers  for  each  switch  and  each  group  of 


94  GENERAL  RAILWAY  SIGNAL  COMPANY 


signals.  This  would  mean  that  a  cross  applied  to  a  given 
switch,  for  example,  would  merely  make  that  particular  func- 
tion inoperative  without  interfering  with  any  of  the  other 
functions.  The  use  of  individual  cross  protection  circuit 
breakers  requires  the  running  of  a  separate  return  wire  for 
each  of  the  functions  or  groups  of  functions  concerned,  and 
dispenses  with  the  main  common  previously  mentioned. 

The  device  (Fig.  68)  employed  for  this  purpose  consists  of 
a  modified  form  of  the  regular  polarized  relay,  provided  with 
suitable  contacts  and  a  restoring  handle.  The  contact  pres- 
sure is  increased  over  that  of  the  regular  polarized  relay,  at  the 
same  time  retaining  the  relay's  sensitiveness  to  reverse  currents, 
the  contacts  are  heavier  in  design,  and  the  iron  in  the  magnet 
is  so  distributed  that  a  powerful  magnetic  blowout  is  obtained 
which  effectually  extinguishes  any  arc  resulting  from  currents 
flowing  through  the  contacts  at  the  time  of  their  opening. 
The  principles  involved  in  the  making  and  breaking  of  the 
circuits,  and  in  the  restoration  of  the  relay  armature  to  the 
operating  position  after  having  been  reversed,  are  similar  to 
those  of  the  cross  protection  circuit  breaker  previously  de- 
scribed. The  device,  as  installed,  is  enclosed  in  a  sealed  case 
(Fig.  69)  to  prevent  any  improper  manipulation  of  the 
circuit  breaker  parts. 

This  protective  apparatus  is  mounted  on  the  terminal  board 
of  the  interlocking  machine,  occupying  the  same  space  as  the 
regular  polarized  relay.  The  device,  which  is  exceedingly 
simple  in  construction,  is  in  no  way  subjected  to  weather  con- 
ditions and  is  much  more  accessible  than  if  located  in  the 
field  at  the  various  switches  and  signals,  as  is  the  ordinary 
practice  with  some  systems  employing  individual  cross  pro- 
tection. 

TESTS  FOR  CROSS  PROTECTION 

It  has  previously  been  stated  that  all  contacts  and  connec- 
tions depended  upon  for  cross  protection  are  under  a  constant 
automatic  check  during  the  regular  operation  of  the  different 
functions;  therefore  tests  on  the  cross  protection  system  are 
in  no  way  requisite  in  the  same  sense  that  tests  are  necessary 
on  switch  points,  to  determine  with  what  maximum  opening 
the  switch  points  can  be  locked.  It  is  considered,  however, 
that  the  satisfaction  of  having  a  working  demonstration  of 
the  existence  of  the  cross  protection  more  than  repays  the 
slight  trouble  involved  in  making  it  one  of  the  points  to  be 
checked  up,  on  the  regular  inspection  trip. 

The  time  chosen  for  conducting  such  a  test  should  be  when 
the  voltage  on  the  system  is  at  the  highest  point  attained  in 
service.  This  will  be  when  the  interlocking  battery  is  being 
charged,  at  which  time  the  current  will  run  up  above  140 
volts. 

The  tests  on  the  various  switch  functions  may  be  secured 
by  making  a  connection  between  the  normal  and  reverse  operat- 
ing wires  on  the  pole  changer. 


ELECTRIC   INTERLOCKING   HANDBOOK 


95 


FIG.  68.     INDIVIDUAL  CROSS  PROTECTION  CIRCUIT 

BREAKER 
Cover  removed. 


FIG.  69. 


INDIVIDUAL  CROSS  PROTECTION  CIRCUIT 
BREAKER 


96  GENERAL  RAILWAY  SIGNAL  COMPANY 


In  testing  signals,  the  necessary  energy  may  be  obtained  at 
the  nearest  switch  mechanism,  since  one  of  the  switch  control 
wires  is  always  connected  to  battery  positive  (Fig.  64).  The 
test  should  be  made  by  connecting  energy  onto  the  signal 
control  wire  as  near  as  possible  to  the  signal  motor,  and  if  the 
signal  circuit  is  connected  to  the  common  return  wire  through 
one  or  more  switch  circuit  controllers,  the  energy  should  be 
applied  to  this  wire,  care  being  taken  to  first  open  the  connec- 
tion to  the  main  common  wire.  Failure  to  open  this  connec- 
tion to  common  in  all  probability  will  result  in  blowing  a  fuse 
in  the  switch  circuit  from  which  the  energy  is  being  taken  for 
the  test,  since  under  these  conditions  a  short  circuit  to  the 
common  return  wire  is  created. 

Where  the  plant  has  been  sectionalized,  one  or  two  functions 
in  a  given  section  should  be  crossed  up  with  wires  taking  energy 
from  each  of  the  other  sections.  In  case  the  functions  in  the 
various  sections  are  widely  separated,  these  crosses  may  be 
made  between  the  binding  posts  in  the  terminal  board  of  the 
interlocking  machine,  to  avoid  running  a  conductor  long  dis- 
tances over  ground.  This  test  will  insure  that  the  proper 
division  of  the  functions  was  made  at  the  time  of  installation, 
and  that  no  undesirable  connections  have  since  been  made. 

For  the  first  test  after  an  interlocking  system  has  been 
installed  it  may  be  well  to  connect  an  adjustable  resistance  in 
the  wires  used  in  making  the  crosses,  starting  with  the  resist- 
ance all  in  and  gradually  cutting  it  down  until  the  circuit 
breaker  opens.  For  the  periodical  tests  which  some  railway 
companies  carry  out  this  resistance  is  generally  considered 
unnecessary. 


ACCESSORIES 


MODEL  3  FORM   D  SWITCH  CIRCUIT  CONTROLLERS 


FIG.  70.     MODEL  3  FORM  D  SWITCH 

CIRCUIT  CONTROLLER 
Two  circuits,  normal  or  reverse. 


FIG.  71.     MODEL  3  FORM  D 

SWITCH  CIRCUIT  CONTROLLER 

Two  circuits  normal  and  two 

reverse. 


FIG.  72.     MODEL  3  FORM  D  SWITCH 

CIRCUIT  CONTROLLER 
Four  circuits  normal  and  four  reverse. 


f 

98  GENERAL  RAILWAY  SIGNAL  COMPANY 

MODEL   5  FORM  A  SWITCH   CIRCUIT  CONTROLLER 

The  Model  5  Form  A  switch  circuit  controller  arranged  for 
selecting  signal  circuits  is  shown  by  Figs.  73,  74  and  75.  The 
operation  of  the  contacts,  which  are  forced  open  and  forced 
closed,  is  effected  through  a  cam  movement,  which  causes 
all  wear  to  come  on  heavy  iron  parts  and  not  on  the  contacts. 

The  contacts  may  be  adjusted  in  pairs  to  make  normal  or 
reverse  contact  as  required.  One  pair  is  adjusted  by 
means  of  the  screw  jaw  on  the  connecting  rod  and  the  other 
pair  by  means  of  the  cam  (Fig.  187),  the  parts  after  adjust- 
ment being  positively  locked  against  working  loose.  The 
contacts  and  binding  posts  are  mounted  on  a  vertical  panel 
which  gives  convenient  access  to  the  binding  posts  when 
"connecting  up  "  and  permits  ready  inspection  of  the  contacts. 


FIG.  73.     MODEL  5  FORM  A  SWITCH  CIRCUIT  CONTROLLER 

Two  circuits  normal  and  two  reverse,  or  four  circuits  normal,  or  four 

circuits  reverse. 

The  case  is  provided  with  main  and  supplementary  covers 
as  shown  by  Fig.  74,  the  latter  protecting  the  contacts  from 
frost  and  condensation  at  all  times,  and  when  the  main  cover 
is  open,  from  rain.  The  trunking  cap  and  operating  crank 
may  be  applied  to  either  side  of  the  circuit  controller  as  proves 
most  convenient  in  installation. 


THREE  POSITION  D.  C.  MOTOR   RELAY 

The  Three  Position  D.  C.  Motor  relay  is  especially  designed 
for  wireless  control  automatic  block  signaling,  but  is  readily 
adapted  for  use  with  three  position  polarized  line  circuits. 

The  operating  mechanism  consists  of  a  small  direct  current 
motor  having  powerful  permanent  magnet  fields  with  ample 
air  gap  between  the  armature  and  pole  pieces.  The  contacts 
are  moved  from  the  de-energized  position  to  either  of  the 


ELECTRIC   INTERLOCKING   HANDBOOK  99 


FIG.  74.     MODEL  5  FORM  A  SWITCH  CIRCUIT  CONTROLLER  FOR  SELECTING 
SIGNAL  CIRCUITS — MAIN  AND  SUPPLEMENTARY  COVERS  OPEN 


FIG.  75.    MODEL  5  FORM  A  SWITCH  CIRCUIT  CONTROLLER  FOR  SELECTING 

SIGNAL  CIRCUITS — MAIN  COVER  OPEN 

Two  circuits  normal  and  two  reverse,  or  four  circuits  normal, 
or  four  circuits  reverse. 


100 


GENERAL  RAILWAY  SIGNAL  COMPANY 


energized  positions  by  the  rotary  motion  of  the  motor  armature, 
the  movement  of  which  is  transmitted  to  the  contacts  by 
suitable  link  connections.  The  closing  of  one  or  the  other 
sets  of  contacts  is  accomplished  by  a  partial  rotation  of  the 
armature,  the  direction  being  dependent  on  the  polarity  of 
the  operating  current. 

The  contacts  have  the  same  opening  and  pressure,  and  are 
similar  in  design  t'o  those  used  in  the  regular  Model  9  D.  C. 
relay.  The  maximum  equipment  of  contacts  in  the  four  way 
relay,  shown  in  Fig.  76,  is  four  normal  and  four  reverse, 
with  four  contacting  fingers.  It  is  to  be  noted  that  when 
used  in  connection  with  wireless  signaling  on  polarized  track 
work,  the  signal  control  is  broken  through  one  set  of  con- 


FIG.  76.     THREE  POSITION  D.  C.  MOTOR  RELAY 
Four  way. 


tacts  only,  while  in  the  polar-neutral  relay  the  control  must 
be  broken  through  both  polar  and  neutral  contacts.  This 
same  holds  true  for  the  track  control,  which,  owing  to 
the  decreased  resistance  of  the  contacts  introduced  into  the 
circuit,  means  that  cut-sections  can  be  employed  to  as  great 
an  extent  in  polarized  track  circuit  work,  through  the  use  of 
this  relay,  as  in  the  case  of  neutral  track  circuits  employing 
the  ordinary  two  position  relay. 

The  relay  has  several  other  important  features  which  should 
be  noted.  The  design  is  such  that  the  chance  of  having  the 
polarity  reversed  by  a  large  flush  of  current  or  by  lightning  is 
so  remote  as  to  be  negligible.  The  relay  is  not  subject  to 
residual  magnetism  troubles  in  any  way,  as  its  operation 
depends  on  current  only,  and  not  on  electro-magnetic  traction. 
This  being  the  case,  the  drop  away  (50  per  cent,  of  the  normal 
pick  up)  cannot  change  with  time,  and  once  fixed,  always 


ELECTRIC  INTERLOCKING 'HANDBOOK1 


101 


remains  the  same.  The  overall  dimensions  are*  such  *&&'  "to 
permit  its  installation  in  the  space  required  by  a  D.  C.  tractive 
type  relay  having  the  same  contacting  capacity. 


TRACTIVE   TYPE  D.  C.  RELAYS 


FIG.  77. 


MODEL,  9  D.  C.  SHELF  RELAY 
Four  way. 


FIG.  78. 


MODEL  9  D.  C.  WALL  RELAY 
Four  way. 


102 


GENERAL   RAILWAY  SIGNAL  COMPANY 


ELECTRIC    INTERLOCKING    HANDBOOK 


103 


TRACK   DIAGRAMS  AND   MANIPULATION   CHARTS 

To  facilitate  the  manipulation  of  the  levers  of  the  inter- 
locking machine,  it  is  customary  to  mount  within  full  view  of 
the  leverman  a  diagram  of  the  track  layout  showing  the  rela- 
tive location  of  all  interlocked  switch  and  signal  functions, 
also  a  chart  listing  the  various  routes  through  the  plant  and 
the  order  in  which  the  levers  are  to  be  moved  in  setting  up 
each  of  these  routes.  By  referring  to  the  chart,  the  leverman 
is  guided  in  manipulating  the  levers  in  the  sequence  imposed 
by  the  mechanical  locking  between  levers,  thus  aiding  him 
greatly  in  the  handling  of  the  traffic  passing  through  the  plant. 


FIG.  80  FIG.  81 

MODEL  9  D.  C.  INDICATOR 

Four  way. 

The  track  diagram  and  manipulation  chart  are  usually  com- 
bined in  one  plan  and  mounted  in  a  single  frame,  unless  their 
combined  size  is  prohibitively  large,  in  which  case  they  are 
framed  separately.  

INDICATORS 

For  a  long  time  it  has  been  customary  to  give  to  the  lever- 
man an  indication  of  the  trains  approaching  the  interlocking 
plant;  with  the  advent  of  route  locking  and  the  semi-auto- 
matic control  of  signals,  and  the  consequent  general  use  of 
track  circuits  within  the  interlocking  limits,  this  practice  has 
been  extended  to  indicating  at  the  interlocking  station,  the 


104 


GENERAL  RAILWAY  SIGNAL  COMPANY 


FIG.  82. 


MODEL  9  D.  C.  INDICATOR  GROUP 
Cover  removed. 


condition  of  all  the  track  sections  within  the  plant.  This 
supplements  the  information  given  by  the  track  diagram  and 
manipulation  chart,  and  adds  considerably  to  the  facility 
with  which  the  traffic  is  handled. 

The  approach  sections  are  usually  repeated  by  disc  indicators 
and  the  different  track  sections  between  the  home  signal 
limits  by  semaphore  indicators.  These  are  generally  located 
on  the  wall  of  the  operating  room  near  the  track  diagram, 


FIG.  83.     MODEL  9  D.  C.  INDICATOR  GROUP 


ELECTRIC    INTERLOCKING  HANDBOOK 


105 


FIG.  84.     MODEL  9  D.  C.  INDICATORS.     LAKE  STREET  INTERLOCKING 
PLANT,  CHICAGO  TERMINAL,  C.  &  X.  W.  R'Y 

being  mounted  either  separately  with  individual  covers  or  on 
a  common  frame  with  a  single  cover.  The  indicators,  as  shown 
by  Figs.  81  and  82,  may  be  equipped  with  contacts  and  thus 
perform  the  functions  of  a  relay  in  addition  to  those  of  a 
repeater. 

ILLUMINATED  TRACK  DIAGRAMS 
A  method  of  indicating  the  occupancy  or  non-occupancy 
of  the  various  track  sections,  rather  more  elaborate  than  by 
the  use  of  repeating  indicators,  is  through  the  employment  of 
the  illuminated  track  diagram.  This  type  of  indicator  is 
of  great  assistance  on  extremely  busy  plants  where  it  is 
necessary  to  know  when  a  train  has  cleared  each  route  or 


106 


GENERAL   RAILWAY   SIGNAL   COMPANY 


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SECTION   III 


G.  R.  S.  ALTERNATING   CURRENT 
APPLIANCES 


DESCRIBING  A.  C.  RELAYS  AND  THEIR 
USE  IN  INTERLOCKING  WORK;  ALSO 
SINGLE  AND  DOUBLE  RAIL  A.  C. 
TRACK  CIRCUITS,  AND  TRANSFORMERS 


ALTERNATING  CURRENT  RELAYS 

THE  following  pages  have  been  written  with  the  object  of 
acquainting  those  interested   in   this  type  of  apparatus 
with  the  principal  characteristics  and  proper  application 
of  the  various  alternating  current  relays  manufactured  by  the 
General  Railway  Signal  Company. 

POINTS  TO  BE  CONSIDERED  IN  SELECTING  AN  ALTERNATING 
CURRENT  RELAY 

In  selecting  any  alternating  current  relay  for  a  given  purpose, 
the  following  should  be  taken  into  consideration : 

First — Is  the  device  to  be  used  as  a  track  relay  or  a  line  relay? 

If  it  is  to  be  employed  as  a  track  relay,  in  all  proba- 
bility it  will  be  exposed  to  the  influence  of  traction  or  foreign 
currents,  and  must,  therefore,  be  of  such  design  that  it  will  not 
respond  to  currents  other  than  that  intended  for  its  operation. 
Furthermore,  if  the  track  circuits  are  very  long  or  the  ballast 
very  bad,  or  if  the  relay  is  to  be  located  a  long  distance  from 
its  point  of  connection  to  the  rails,  the  relay  should  necessarily 
require  very  little  energy  from  the  rails  in  order  to  avoid  cut 
sections  or  undue  energy  consumption.  On  the  other  hand, 
when  the  opposite  conditions  exist,  these  relays  need  not  be 
so  highly  efficient  and  consequently  may  be  smaller  and  less 
expensive. 

If  required  for  use  as  a  line  relay  the  device  will  rarely  be 
installed  where  it  will  be  exposed  to  the  influences  of  foreign 
or  traction  currents,  and  when  such  is  the  case,  can  be  of 
simpler,  smaller,  and  less  expensive  design. 

Second  —  Is  two  or  three  position  operation  required? 

In  this  connection  it  should  be  noted  that  the  amount  of 
line  wire  can  frequently  be  reduced  by  the  employment  of 
relays  which  have  normal,  reverse,  and  de-energized  positions. 
To  secure  the  equivalent  of  this  using  two  position  relays  it 
may  be  necessary  to  install  twice  as  many  relays  and  additional 
line  wire.  A  concrete  example  of  this  is  the  application  of 
three  position  relays  to  polarized  track  circuit  work  in  which 
the  caution  and  clear  positions  of  a  signal  are  given  over  the 
track  rails  by  reversing  the  polarity,  and  without  the  use  of 
line  wires  at  all. 

Third  —  How  many  and  what  kind  of  contacts  is  the  relay 
to  have? 

It  frequently  happens  that  as  many  as  ten  or  twelve 
contacts  are  required  and  that  these  contacts  must  carry 
at  comparatively  high  voltage  a  large  amount  of  current; 
in  other  cases  but  few  contacts  and  these  carrying  very 
light  currents  are  necessary.  Furthermore,  contacts  equipped 
with  "magnetic  blowouts"  may  be  needed  to  extinguish  arcs 
which  otherwise  would  be  established  in  the  handling  of  heavy 
direct  currents.  These  are  features  which  often  determine 
the  selection  of  the  relay. 


110  GENERAL  RAILWAY  SIGNAL  COMPANY 


Fourth  —  Generally  speaking,  the  question  of  whether  a 
relay  is  to  be  of  high  or  low  efficiency,  and  whether  it  would 
pay  to  spend  more  or  less  for  it,  should  be  decided  on  the  same 
basis  that  is  used  in  selecting  any  piece  of  apparatus,  viz: 
having  determined  the  total  cost  of  the  device  in  place,  includ- 
ing any  necessary  auxiliary  devices,  it  is  then  proper  to  esti- 
mate the  cost  of  the  energy  required  for  its  operation,  and 
that  relay  which  will  answer  the  purpose  and  cost  the  least, 
considering  first  cost,  energy  consumption,  maintenance  charges, 
interest,  and  depreciation,  should,  of  course,  be  the  one  to  use. 

MODEL  2  FORM  A  POLYPHASE  RELAY 

The  Model  2  Form  A  relay  is  especially  designed  for  power- 
ful and  efficient  operation  on  very  long  track  circuits.  As 


FIG.  86.      MODEL  2  FORM  A  POLYPHASE  RELAY 
Four  way. 

an  evidence  of  this  efficiency,  it  may  be  pointed  out  that  with 
minimum  energy  consumption  it  has  given  perfect  operation  on 
track  circuits  of  from  three  to  four  miles  in  length,  and  with 
ballast  conditions  far  from  favoring  good  track  circuit  operation. 
The  relay  is  operated  by  a  polyphase  motor,  which  consists 
of  a  non-magnetic  rotating  shell  or  "rotor,"  and  fixed  inner 
and  outer  cores,  the  outer  core  being  the  "stator"  on  which 
the  windings  are  placed.  These  windings  are  designed  and 
connected  so  as  to  produce  (with  alternating  current  applied) 
a  rotating  magnetic  field,  which  in  turn  will  induce  currents  in 
the  non-magnetic  rotor  causing  it  to  operate.  (Direct  currents 
cannot  produce  this  rotary  field  and,  therefore,  cannot  cause 
operation.)  The  rotor  is  ordinarily  connected  to  the  con- 
tacts through  the  medium  of  a  pinion  and  sector  arrangement, 
thereby  multiplying  the  effect  of  the  rotor  and  permitting  the 
operation  of  a  large  number  of  contacts  with  a  very  small 


ELECTRIC   INTERLOCKING   HANDBOOK  111 


amount  of  energy  applied.  Furthermore,  as  it  is  possible  to 
supply  most  of  the  energy  to  the  stator  from  a  local  source, 
only  a  small  amount  of  energy  is  required  from  the  rails  to 
cause  the  relay  to  operate.  These  two  points  permit  the 
operation  of  very  long  track  circuits  without  the  use  of  cut 
sections  or  undue  energy  consumption. 

The  relay  is  universal  in  its  application,  in  that  it  may  be 
wound  for  operation  on  steam  roads,  electric  roads  using 
either  A.  C.  or  D.  C.  propulsion,  or  for  operation  as  a  line 
device.  Furthermore,  it  can  be  adapted  for  use  on  any 
frequency  current,  for  two  or  three  position  operation,  and 
may  be  made  fast  or  slow  acting. 

The  contacts  are  unusually  heavy  in  construction  and  are 
so  designed  that  any  combination  of  front,  back,  or  front  and 
back  contacts  can  be  secured,  changes  being  easily  made  on 
the  ground  if  desired.  Special  contacts  equipped  with  the 
"magnetic  blowout"  referred  to  on  page  109  can  also  be  fur- 
nished. The  contact  housing  for  the  four  and  six  way  relays 
accommodate  eight  and  twelve  contact  fingers,  respectively, 
these  controlling  eight  or  twelve  independent  circuits. 

MODEL  2  FORM  B  RELAY 

The  Model  2  Form  B  relay  operates  on  the  same  general 
principles  as  the  Model  2  Form  A,  employing  the  non-mag- 
netic rotor  which  permits  it  to  operate  with  the  same  degree 
of  safety  and  reliability.  It  is  designed  primarily  to  operate 
as  a  line  device  but  may  be  used  in  connection  with  track 
circuits  to  a  limited  extent;  for  instance,  as  a  track  relay  for 
short  track  circuits  on  steam  roads,  or  for  short  double  rail 
track  circuits  on  roads  using  direct  current  for  propulsion. 
While  the  relay's  efficiency  is  approximately  but  half  that  of 
the  Model  2  Form  A  it  compares  well,  nevertheless,  with  other 
A.  C.  relays  on  the  market.  It  operates  on  25  or  60  cycle 
current,  in  two  or  three  positions,  and  can  be  furnished  either 
slow  or  quick  acting. 

The  Model  2  Form  B  relays  have  about  the  same  overall 
dimensions  as  a  D.  C.  relay  of  the  same  contact  capacity,  this 
feature  permitting  their  installation  in  housings  previously 
occupied  by  D.  C.  relays.  The  relay  is  assembled  as  a  shelf 
or  wall  type  device,  as  a  tower  indicator  or  as  an  interlocking 
relay.  The  contacts  are  limited  to  a  maximum  of  four 
front  and  two  back,  or  six  front  and  two  back,"  in  the  four 
and  six  way  relays,  respectively. 

MODEL  3  FORM  B  RELAY 

In  the  Model  3  Form  B  relay,  the  same  construction  is  used 
for  the  housing,  contact  arrangement,  etc.,  as  in  the  Model 
2  Form  B.  The  actuating  movement  is  essentially  the  same 
as  that  of  the  Model  2  Form  B,  with  the  exception  that  it 
operates  in  two  positions  only  and  is  a  single  phase  device. 


112  GENERAL  RAILWAY  SIGNAL  COMPANY 


Due  to  this  feature  the  relay  does  not  require  the  presence  of 
local  energy  which  is  sometimes  difficult  to  provide  for.  The 
relay  is  equipped  with  a  non-magnetic  rotor  and  is  designed 
primarily  for  use  in  connection  with  single  rail  track  circuits 
on  direct  current  electric  traction  roads. 

MODEL  Z  FORM  B  RELAY 

The  Model  Z  Form  B  relay  uses  the  same  housing  and  is 
provided  with  contacts  of  the  same  design  and  arrangement 
as  the  Model  2  Form  B  and  Model  3  Form  B  relays  previously 
described. 

The  Model  Z  relays  are  provided  with  a  bipolar  stator, 
with  windings  on  each  of  the  poles,  and  a  rotary  armature  so 


FIG.  87 

MODEL  2  FORM  B,  A.  C.  RELAY 
MODEL  3  FORM  B,  A.  C.  RELAY 
MODEL  Z  FORM  B,  A.  C.  RELAY 

Six  way. 

shaped  that  when  current  (either  direct  or  alternating)  is 
applied  to  the  windings,  a  uniform  torque  is  produced,  which 
causes  the  rotor  to  operate  through  about  ninety  degrees. 
This  movement  is  transmitted  by  means  of  a  suitable  connec- 
tion to  the  contacts. 

Being  operable  on  direct  current,  the  relay  is  adapted  for 
line  service  only.  Its  exceptionally  high  efficiency  makes  it 
preferable  for  this  type  of  work  where  direct  current  does  not 
exist  on  the  line  and  where  single  phase  operation  is  desired. 
The  relay  operates  in  two  positions  only. 

In  conclusion,  attention  is  directed  to  the  comparatively 
few  types  of  relays  needed  to  cover  the  full  range  of  require- 
ments of  A.  C.  signaling. 


ELECTRIC   INTERLOCKING   HANDBOOK  113 


It  will  be  noted  by  reference  to  the  description  which  has 
preceded : 

First  —  That  but  two  general  forms  of  construction  are 
employed,  viz:  the  larger,  more  efficient  form  (Fig.  86), 
especially  adapted  for  track  circuit  work,  and  the  small,  mod- 
erately efficient  form  (Fig.  87),  especially  designed  for  line 
circuits  and  short  track  circuits. 

Second  —  That  but  two  principles  of  operation  are  used, 
namely :  the  inductive  as  employed  in  the  Model  2  and  Model  3 
relays,  and  the  electro-magnetic  as  employed  in  the  Model  Z 
relays. 

Third  —  That  each  form  is  made  in  two  sizes  to  accommodate 
more  or  less  contacts  as  required. 

With  these  two  forms,  two  principles  of  operation  and 
two  sizes  of  relays,  wound  and  equipped  with  contacts  as  may 
be  necessary,  all  the  requirements  of  A.  C.  signaling  can  be 
met  without  resorting  to  a  greater  number  of  types.  It  will, 
therefore,  be  seen  that  the  G.  R.  S.  relay  construction  has 
placed  A.  C.  relays,  as  regards  the  diversity  of  types  required, 
on  practically  the  same  basis  with  the  relays  used  in  connec- 
tion with  D.  C.  signaling. 


SINGLE  RAIL  ALTERNATING  CURRENT 
TRACK   CIRCUITS 

SINGLE  rail  A.  C.  track  circuits  are  largely  used  at  inter- 
locking plants  in  electrified  territory.  With  this  type  of 
track  circuit,  insulated  joints  are  placed  in  one  rail  only, 
the  other  rail  being  used  in  common  by  the  return  propulsion 
current  and  the  signaling  current  (see  Figs.  88  and  89).  It 
will  be  seen  that  single  rail  track  circuits  are  used  to  best  ad- 
vantage where  there  are  two  or  more  parallel  tracks,  in 
that  the  power  or  common  rail  of  all  these  tracks  can  be  bonded 
together,  thus  preventing  interruption  of  the  propulsion  current 
return  in  the  event  of  a  break  in  the  power  bonding  in  any  one 
of  the  continuous  rails. 

ADVANTAGES 

The  chief  advantage  of  single  rail  track  circuits  as  compared 
to  the  double  rail  type  is  in  its  lesser  cost  and  complication, 
the  double  rail  circuits  requiring  the  installation  of  impedance 
bonds  to  provide  a  continuous  return  for  the  propulsion  cur- 
rent. As  there  are  usually  a  number  of  comparatively  short 
track  circuits  at  an  interlocking  plant,  it  is  seen  that  the  use 
of  double  rail  track  circuits  with  impedance  bonds  would  be 
very  expensive.  It  is  furthermore  true  that  at  many  plants, 
the  track  arrangement  is  such  that  it  would  be  extremely 
difficult  to  secure  space  at  the  bond  locations  for  their  installa- 
tion. 

LIMITATIONS 

Traction  Return.  When  single  rail  track  circuits  are  in- 
stalled, both  rails  cannot  be  retained  for  traction  purposes,  as 
noted  above.  If  the  giving  up  of  one  rail  leaves  insufficient 
return  for  the  propulsion  current,  the  use  of  single  rail  track 
circuits  is  barred  and  double  rail  track  circuits  would  probably 
have  to  be  employed. 

Broken  Rail  Protection.  Single  rail  track  circuits  do  not 
give  broken  rail  protection  due  to  the  cross  bonding  required 
for  traction  purposes,  which  provides  a  number  of  return 
paths  through  the  rails  of  other  tracks  for  the  signaling  current. 
On  this  account  the  use  of  single  rail  track  circuits  should  be 
restricted  to  slow  speed  tracks,  such  for  example  as  in  terminals, 
or  to  siding  tracks. 

Length.  The  permissible  length  of  single  rail  track  circuits 
is  limited  either  by  ballast  conditions,  by  the  traction  drop  in 
the  return  rail  between  the  points  of  connection  of  the  trans- 
former and  the  track  relay  to  the  common  rail,  or  by  the  com- 
bination of  ballast  and  drop.  The  Model  2  Form  A  relay  as 
ordinarily  constructed  is  capable  of  carrying  10  amperes  direct 
current  through  its  track  winding  without  overheating  or 
being  caused  to  open. 

The  drop  in  the  common  rail  has  the  effect  of  sending  direct 
current  from  the  common  rail  through  the  transformer,  through 


ELECTRIC   INTERLOCKING   HANDBOOK  115 


the  signaling  rail,  the  track  winding  of  relay  and  back  to  the 
common  rail,  this  effect  being  maximum  when  a  train  is  on 
the  transformer  end  of  the  track  circuit,  thereby  cutting  out 
the  transformer  resistance  and  allowing  the  full  drop  to  be 
effective  through  the  signaling  rail  and  relay  in  series. 

In  view  of  the  fact  that  the  common  return  rail  has  a  neg- 
ligible resistance,  there  are  times  when  it  can  be  assumed  that 
all  of  this  drop  is  effective  across  the  relay,  and  to  prevent  a 
prohibitive  amount  of  direct  current  from  flowing  through 
the  relay,  under  ordinary  conditions  a  limiting  resistance  is 
added  in  series  with  the  relay. 

If  however  the  track  circuit  is  long  or  the  ballast  bad,  the 
traction  drop  will  in  all  probability  be  excessive,  thereby 
requiring  that  the  limiting  resistance  be  high,  which  in  turn 
necessitates  that  a  correspondingly  high  A.  C.  voltage  be 
impressed  across  the  rails  at  the  relay  location  in  order  to 
secure  operation;  this  A.  C.  voltage  is  limited  since  as  the 
voltage  is  increased  the  current  leakage  between  the  rails 
throughout  the  length  of  the  track  circuit  increases  very 
rapidly.  To  take  care  of  such  a  condition  an  impedance  hav- 
ing low  ohmic  resistance  to  direct  current,  but  high  resistance 
to  alternating  current,  may  be  shunted  across  the  relay  ter- 
minals, this  permitting  a  large  amount  of  direct  current 
to  flow  through  the  relay  and  impedance  combined  with- 
out causing  more  than  10  amperes  direct  current  to  flow 
through  the  relay;  a  unit  of  low  resistance  is  still  required, 
being  connected  in  series  with  the  relay  and  impedance,  this 
resistance  necessarily  being  in  the  nature  of  a  grid  since  it 
has  to  carry  a  comparatively  large  amount  of  direct  current. 
With  this  arrangement  the  transformer  should  be  designed  to 
stand  a  large  amount  of  direct  current  through  its  secondary 
winding  without  having  its  A.  C.  voltage  seriously  affected. 

Under  the  conditions  ordinarily  found  in  terminals  or  where  it 
is  permissible  to  use  single  rail  track  circuits,  it  will  be  found  that 
the  use  of  a  resistance  in  series  with  the  relay  is  adequate  to  se- 
cure proper  operation,  it  being  necessary  only  in  rare  cases  to  em- 
ploy the  impedance  shunted  around  the  terminals  of  the  relay  as 
above  described. 

ENERGY  REQUIRED 

The  energy  required  for  the  operation  of  single  rail  track 
circuits  depends  upon  the  amount  of  traction  drop  in  the  com- 
mon rail  and  upon  the  ballast  conditions.  In  an  interlocking 
plant  where  the  track  circuits  may  average  500  feet  in  length, 
the  energy  per  track  circuit,  employing  the  Model  2  Form  A 
track  relay,  should  not  exceed  the  figures  given  below: 

Total  Energy  Required  for  Track 
Circuit  and  Relay  Local 

25  cycle  current, 30  volt  amperes     25  watts 

60  cycle  current, 40  volt  amperes     30  watts 

NOTE. — The  Model  2  Form  A  track  relay,  quick  acting  and  designed  to 
stand  10  amperes  direct  current,  has  a  resistance  of  about  one-half  ohm. 


116 


GENERAL  RAILWAY  SIGNAL  COMPANY 


TYPES  OF  SINGLE  RAIL  TRACK  CIRCUITS 

In  the  past  the  common  practice  when  installing  single 
rail  A.  C.  track  circuits  has  been  to  locate  the  track  trans- 
former at  one  end  of  the  track  circuit  and  the  relay  with  its 
housing  and  auxiliary  apparatus  at  the  other  end;  this  re- 
quires that  the  relay  must  be  repeated  into  the  interlocking  sta- 
tion to  operate  other  relays  or  indicators.  A  simplified  dia- 
gram of  such  a  circuit  is  illustrated  by  Fig.  88. 

In  sharp  contrast  with  this  is  shown  in  Fig.  89,  the  method 
which  can  be  used  when  a  high  efficiency  polyphase  relay  such 
as  the  Model  2  Form  A  is  employed.  By  feeding  the  track 
circuit  from  a  central  source  and  extending  the  relay  leads 


INTERLOCKING   STAT\ON  LIMITS 

r 1 


r 

i  — 

HIGH  VOLTAGE.  1 

i 
i 

WV  PRIMARY 

r 

^AA|    A«5rORMER| 

1 

fl      1             /X 

1 

'  —  -i  J  ,  >-KEPEATIHG, 

1 
1 

|Er    ]  INDICATOR 

1  —  -J 

A/vJ 

TRACK 

Wd 

TRANSFORMER 

COMMON  RETURN  RAIL 

•i  —  i 

TRACK 

RELAY 

. 

FIG.  88.     SINGLE  RAIL  A.  C.  TRACK  CIRCUIT 
Track  relay  and  transformer  located  at  track  circuit. 

from  the  track  circuit  into  the  station,  the  amount  of  apparatus 
can  be  cut  down,  maintenance  costs  reduced  to  a  minimum, 
and  certain  safety  features,  not  obtainable  in  the  other  arrange- 
ment, secured. 

It  will  be  noted  that  in  the  central  energy  scheme,  the 
vital  parts  of  the  track  circuit  are  located  in  the  station  directly 
under  the  eye  of  the  maintainer  which  permits  adjustments  to 
be  made  under  the  most  favorable  conditions.  Due  to  the 
simplicity  and  accessibility  of  this  type  of  track  circuit,  main- 
tenance is  reduced  to  a  minimum. 

A  considerable  amount  of  apparatus  is  saved  by  this  kind  of 
an  installation,  since  secondary  relays  with  their  track  boxes, 
additional  wiring  and  fusing,  are  not  required :  furthermore, 
the  numerous  track  transformers  which  otherwise  would  have 


ELECTRIC   INTERLOCKING   HANDBOOK 


117 


to  be  distributed  from  one  end  of  the  interlocking  plant  to 
the  other  are  eliminated  due  to  the  circuits  being  fed  from  one 
central  point.  The  resistance  of  the  leads  from  the  track 
circuit  to  the  relay  and  transformer,  constitute  a  part  of  the 
limiting  resistance  required  in  series  with  these  pieces  of  ap- 
paratus. 

A  safety  feature  obtainable  in  the  central  energy  scheme 
which  cannot  be  overlooked  is  in  the  protection  against  crosses. 
It  will  be  noted  by  reference  to  Fig.  88  that  a  cross  at  X  will 
cause  false  operation  of  the  repeating  relay  in  the  station, 
whereas  a  similar  cross  in  Fig.  89  prevents,  as  it  should, 
operation  of  the  relay.  Every  step  toward  simplicity  is  a 


INTERLOCKING  STATION  LIMITS 

l~" 1 

l~f     HIGH  VOLTAGE.        I 


i    IW 

in 

wv 

A/V 

TKMISf 

RY 

ORMER' 

i 
i 
i 
i 

L 

P 

/  X 

J 

M 

-TRACK 
RELAY 
(INDICATING) 

_i 

^s  MULTIPLE   CONDUCTOR 

BONDED  TO  ALL  COMMON 
RETURN  RAILS 

n 

J 

ALL  OTHER  COMMON  RETURN  RAILS 

FIG.  89.     SINGLE  RAIL,  A.  C.  TRACK  CIRCUIT 
Central  energy  scheme. 

step  towards  safety  and  this  central  energy  control  is  the 
last  word  in  simplicity  as  regards  track  circuits. 

The  high  efficiency  of  the  Model  2  Form  A  relay  especially 
adapts  it  for  this  kind  of  work,  the  relay  requiring  but  a  small 
amount  of  current  from  the  rails,  while  a  comparatively  large 
amount  is  supplied  at  the  station  for  the  local  phase  of  the  relay. 
The  relay  may  be  equipped  with  an  indicator  blade  and 
located  in  plain  sight  of  the  leverman,  thus  dispensing  with  the 
necessity  of  repeating  indicators  which  might  otherwise  be 
required  for  this  purpose. 

TYPICAL  INSTALLATION  OF  THE  CENTRAL  ENERGY  SCHEME 

Fig.  90,  which  is  typical  of  a  large  G.  R.  S.  installation, 
illustrates  the  extension  of  the  principle  of  Fig.  89  into  the 
complete  wiring  required  in  connection  with  this  type  of  track 


118 


GENERAL  RAILWAY   SIGNAL  COMPANY 


Interlocking  Station  Limits 


Controller 
On  lever  tatch 
A.c  Lock  on 
5n  lever 


FIG.  90.     SECTION  OF  INTERLOCKING  PLANT 
Showing  use  of  central  energy  scheme  for  track  circuit  control. 


ELECTRIC   INTERLOCKING   HANDBOOK  119 


circuit  work.  It  also  indicates  the  control  between  the  inter- 
locking machine  and  the  switch  and  signal  functions  in  the 
given  section  of  track,  and  shows  the  method  of  controlling 
the  switch  lever  locks  and  track  indicators  through  the  track 
relay. 

The  track  relays  and  transformers  are  shown  located  in  the 
station,  the  latter  being  installed  in  duplicate  to  prevent  any 
interruption  of  service  should  anything  happen  to  one  of 
the  transformers.  It  will  be  noted  that  the  transformers, 
besides  feeding  the  track  circuits,  are  used  to  furnish  energy 
for  the  signal  lighting  and  the  operation  of  all  A.  C.  appa- 
ratus. The  track  winding  of  these  transformers  is  brought  to 
a  buss  bar  on  the  distributing  switchboard,  the  individual 
leads  of  the  various  track  circuits  being  connected  to  this  buss. 
It  is  general  practice  where  the  track  circuits  vary  sufficiently, 
or  where  any  of  them  are  located  far  enough  from  the  station 
to  require  much  more  voltage  than  the  others,  to  provide  the 
track  winding  of  the  transformer  with  a  number  of  taps  which 
are  carried  to  different  buss  bars,  the  individual  leads  of  the 
different  track  circuits  being  taken  from  one  buss  or  the 
other  as  required. 


IMPEDANCE    BONDS    FOR    DOUBLE    RAIL 

ALTERNATING  CURRENT  TRACK 

CIRCUITS 

WHEN  it  is  desired  to  install  A.  C.  track  circuits  and 
both  rails  must  be  retained  for  propulsion  purposes, 
double  rail  track  circuits,  such  as  are  shown  by  the 
typical  circuit,  Fig.  238,  must  be  employed.     It  will  be  noted 
that  the  track  is  divided  into  sections  of  varying  length  by 


FIG.  91.     METHOD  OF  INSTALLING  SIZE  1  FORM  C  IMPEDANCE  BONDS 


means  of  insulated  rail  joints.  Impedance  bonds  are  installed 
at  such  locations  for  the  purpose  of  providing  around  the  joints 
a  low  resistance  path  for  the  return  D.  C.  propulsion  current, 
while  not  permitting  the  passage  of  the  A.  C.  signaling  current. 
The  bonds  consist  of  a  few  turns  of  heavy  copper  wound 
about,  but  insulated  from,  a  laminated  iron  core,  the  con- 
nections to  the  rails  being  so  made  that  the  traction  current 
has  no  magnetic  effect  on  the  bond,  provided  an  equal  amount 
is  flowing  in  each  of  the  rails.  If,  however,  more  current  is 
flowing  in  one  rail  than  in  the  other,  there  will  be  a  tendency 
to  saturate  the  iron  core  and  thereby  reduce  the  impedance 
of  the  bond.  This  effect,  which  is  called  "unbalancing," 
is  limited  by  introducing  an  air  gap  into  the  magnetic  circuit, 


ELECTRIC  INTERLOCKING   HANDBOOK 


121 


the  bonds  ordinarily  being  designed  to  stand  20  per  cent. 
unbalancing  without  a  decrease  of  more  than  10  per  cent,  in 
impedance. 

The  size  of  the  bond  to  be  installed  is  dependent  upon  the 
amount  of  current  the  bond  will  have  to  carry,  the  impedance 
to  which  it  must  be  wound  (this  being  more  or  less  dependent 
upon  the  length  of  the  track  circuit),  and  upon  the  amount  of 
unbalancing  to  be  taken  care  of.  Where  good  traction  bond- 
ing can  be  maintained  a  less  amount  of  unbalancing  can  be 
figured  upon,  and  hence  a  smaller  size  of  bond  employed. 


1 

innn 

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Bare  Stranded]  | 

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3 

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Transformer 
Leads. 

li 
il 





JUL 



r1! 

Reldy 
Leads 

FIG.  92. 


METHOD  OF  INSTALLING  SIZE  2  FORM  B  AND  SIZE  3 
FORM  A  IMPEDANCE  BONDS 


Dimension 

Size  2  Form  B  Bond 

Size  3  Form  A  Bond 

A 
B 
C 

20%  inches 
24y2  inches 
13%  inches 

18%  inches 
17%  inches 
11%  inches 

The  Size  1  Form  C  bond,  which  is  the  largest,  is  installed 
only  where  the  heaviest  traffic  requirements  are  to  be  met,  the 
size  of  the  bond  requiring  that  it  be  located  outside  of  the  rails. 
The  Size  2  Form  B  and  Size  3  Form  A  bonds  are  of  such  dimen- 
sions as  to  permit  their  being  installed  between  the  rails. 
These  smaller  bonds  are  furnished  with  sloping  covers  to  pre- 
vent their  being  caught  by  dragging  train  parts,  and  are 
especially  designed  to  have  their  leads  brought  out  of  the  case 
in  a  manner  to  facilitate  connection  to  the  rails. 


TRANSFORMERS 
HIGH  TENSION  LINE  TRANSFORMERS 

THE  Type  L  transformer  is  a  single  phase,  oil  immersed, 
self  cooled,  pole  type  transformer,  designed  to  step  down 
the  transmission  line  voltage  (6,600  volts  maximum)  at 
signal  and  track  feed  locations,  to  the  voltage  required  for  the 
operation  of  the  signal  system. 


FIG.  93. 


VIEW  OF  TYPE  L  TRANSFORMER  SHOWING 
TERMINAL  BOARDS 


FIG.  94.     TYPE  L  HIGH  TENSION  LINE  TRANSFORMER 

The  combinations  in  which  these  transformers  are  made  up 
are  as  follows : 

1.  High  tension  primary  winding  and  low  tension  secondary 
winding  for  feeding  relay  locals,  signal  mechanisms,  and  lights. 

2.  High  tension  primary  winding  and  low  tension  secondary 
winding  for  feeding  track  circuits. 


ELECTRIC   INTERLOCKING   HANDBOOK  123 


3.  High  tension  primary  winding  and  low  tension  secondary 
windings,  one  for  feeding  relay  locals,  signal  mechanisms  and 
lights,  and  one  or  two  for  feeding  track  circuits. 

The  primary  or  high  tension  winding  may  be  equipped 
with  5  and  10  per  cent,  taps  brought  to  a  suitable  porcelain 
terminal  block,  which  ordinarily  is  located  below  the  oil 
level  to  minimize  the  liability  of  lightning  arcing  from  post  to 
post.  The  secondary  leads  and  taps  are  brought  to  a  sepa- 
rate porcelain  terminal  board  located  above  the  oil  level. 

The  transformer  windings  are  contained  in  a  cast  iron, 
water-proof  case,  which  is  fitted  with  lugs  to  take  the  hanger 
irons  necessary  for  mounting. 

These  transformers  are  built  with  the  same  relative  polarity 
and  are  so  constructed  that  reversing  the  polarity  of  the  track 
feed  may  be  accomplished  on  the  terminal  block  inside  the 
transformer  without  changing  the  permanent  exterior  circuit 
connections. 


FIG.  95.     TYPE  K  SECONDARY  TRACK  TRANSFORMER 

Core  losses  and  copper  losses  are  lower  and  the  efficiency 
higher  than  usually  is  obtainable  on  this  special  class  of  trans- 
formers. Good  regulation  on  low  power  factor,  low  exciting 
current  and  high  insulation  (insulation  tests  being  50  per  cent, 
above  A.  I  E.  E.  standards)  are  features  which  combine 
to  form  an  exceptional  transformer  in  point  of  long  life  and 
safety.  The  transformer  design  is  strictly  in  accordance  with 
R.  S.  A.  specifications. 

SECONDARY  TRACK  TRANSFORMERS 

The  Type  K  secondary  track  transformer  as  illustrated  by 
Fig.  95  is  of  the  air  cooled  type  and  is  especially  designed 
for  feeding  individual  track  circuits,  being  used,  however,  to 
some  extent,  in  connection  with  low  voltage  tungsten  light- 
ing. 

The  transformers  are  ordinarily  made  up  with  one  high 
tension  primary  winding  and  one  low  tension  secondary 
winding,  this  latter  being  provided  with  taps  for  the  adjust- 
ment of  the  track  circuit  feeds.  The  primaries  are  wound 
for  any  voltage  up  to  440  as  specified  and  as  ordinarily 
installed  are  connected  to  the  low  tension  secondary  of  the 
line  transformer.  These  connections  can  be  made  and  the 


124  GENERAL  RAILWAY  SIGNAL  COMPANY 


track  transformer  housed  in  the  relay  box  ordinarily  installed 
at  signal  locations. 

The  cover  of  the  transformer  is  provided  with  binding  posts 
for  both  high  and  low  tension  windings.  The  case  is  of  cast 
iron,  light  in  weight,  and  is  provided  both  with  lugs  for  hang- 
ing, and  with  feet  to  permit  of  the  device  being  mounted  as 
desired. 

The  same  exceptional  efficiency,  regulation,  and  low  exciting 
current  are  obtained  in  this  class  of  transformer  as  in  the  Type 
L  transformers,  previously  described. 


SECTION   IV 


SIGNAL    LIGHTING   AT    INTERLOCKING 
PLANTS 


COVERING  RECOMMENDED  PRACTICE 
FOR  ELECTRIC  LIGHTING  AS  TO  THE 
ARRANGEMENT  OF  LAMPS,.  SOURCE 
OF  POWER,  AND  PRECAUTIONS  TO 
OBSERVE 


SIGNAL  LIGHTING  AT  INTERLOCKING 
PLANTS 

THE  question  as  to  whether  oil  or  electricity  is  to  be  used 
for  lighting  the  signals  at  electric  interlocking  plants,  de- 
pends on  what  is  most  economical  and  satisfactory  under 
the  particular  conditions  existing  at  each  separate  plant. 

In  many  cases  a  decision  as  to  the  type  of  lighting  best 
adapted  to  a  given  plant  can  be  easily  reached.  For  example : 
If  commercial  power  of  proper  voltage  is  available  at  low 
cost,  or  if  alternating  current  is  employed  in  connection  with 
the  signaling,  it  will  undoubtedly  be  found  desirable  to  light 
the  lamps  electrically;  this  is  especially  so  if  the  plant  is  a 
very  large  one,  as  at  such  a  point  the  oil  lamps  would  require 
a  special  force  of  lampmen  for  their  maintenance.  On  the 
other  hand,  if  commercial  power  is  not  available  or  can  be 
secured  only  at  a  high  rate,  or  if  the  plant  is  so  small  that  oil 
lamps  could  be  cared  for  by  the  force  regularly  employed,  it 
will  probably  be  found  most  economical  to  use  oil  lighting. 

In  cases  where  the  course  to  be  followed  is  not  so  evident,  a 
careful  estimate  of  the  initial  expense  involved  and  of  the  cost 
of  operation  and  maintenance,  should  be  prepared  before  a 
decision  is  reached.  In  the  case  of  oil  lighting  it  is  merely 
necessary  to  consider  the  cost  of  the  lamps,  oil,  maintenance, 
etc.  In  the  case  of  electric  lighting,  however,  a  number  of 
other  considerations  enter  into  the  problem  as  outlined  on 
the  following  pages. 

TYPE  AND  ARRANGEMENT  OF  BULBS  IN  SIGNAL  LAMPS 

The  bulbs  used  in  this  type  of  work  are  ordinarily  of  low 
candle  power,  it  having  been  found  that  ample  light  is  secured 
from  bulbs  of  two  or  four  candle  power.  When  the  lighting  is 
operated  at  110  volts,  the  carbon  filament  type  is  installed,  it 
being  considered  that  metallic  filament  bulbs  of  such  low 
candle  power  are  too  frail  to  be  reliable  when  designed  for 
operation  on  this  voltage.  Where  it  is  possible,  however,  to 
furnish  current  at  a  potential  of  from  6  to  12  volts,  the  high 
efficiency  of  the  metallic  filament  type  can  readily  be  made 
use  of. 

POWER  REQUIRED   FOR  OPERATION   OF 
INCANDESCENT     LAMPS 


CARBON  FILAMENT 

METALLIC  FILAMENT 

Candle 
Power 

110  Volts 

55  Volts 

10-13  Volts 

4-6  Volts 

Watts 

Watts 

Watts 

Watts 

2 

10 

10 

.. 

2V2 

4 

20 

20 

5 

5 

NOTE. — Values  approximate. 


128  GENERAL  RAILWAY  SIGNAL  COMPANY 


In  determining  the  arrangement  of  the  bulbs  in  each  signal 
lamp,  the  first  consideration  is  to  insure  the  signals  against 
ever  being  without  light.  On  this  account,  general  practice  has 
been  to  have  each  signal  lamp  contain  two  bulbs,  connected 
in  multiple,  it  being  highly  improbable  that  both  will  burn 
out  at  the  same  time.  The  reduced  brilliancy  of  the  signal 
light,  resulting  from  the  burning  out  of  one  of  the  bulbs, 
causes  the  failure  to  be  quickly  detected  and  permits  the 
necessary  renewal  to  be  made  at  once. 

Where  two  bulbs,  burning  in  multiple,  give  more  than  the 
amount  of  light  required,  an  economy  can  be  effected  without 
sacrificing  reliability  by  employing  "cut  in"  relays  which 
permit  the  burning  of  but  one  of  the  bulbs  at  a  time.  The 
coil  of  this  "cut  in"  relay  is  connected  in  series  with  the  bulb 
that  is  to  burn  normally,  a  back  contact  on  the  relay  being 
arranged  to  connect  the  reserve  bulb  across  the  lighting  mains 
in  the  event  of  failure  of  the  one  in  service. 

Another  way  to  reduce  the  energy  consumption  and  still 
retain  the  necessary  reserve,  is  to  use  the  high  efficiency 
metallic  filament  bulbs  connected  in  multiple.  As  stated 
above,  a  low  candle  power  bulb  of  this  type  to  be  reliable 
must  be  operated  on  low  voltage. 

NORMAL  SOURCE  OP  POWER  AND  THE  NECESSARY  RESERVE 

Having  touched  upon  -the  type  and  arrangement  of  the 
bulbs  to  be  used  in  signal  lamps,  the  next  consideration  should 
be  with  regard  to  the  normal  power  supply  and  what  reserve 
should  be  provided  to  keep  the  lights  burning  in  case  of 
emergency. 

It  is  recommended  as  good  practice  that  the  signal  lights 
should  be  operated  from  a  commercial  source,  the  control 
being  arranged  so  that  the  lighting  systems  will  be  quickly 
transferred  on  to  the  110  volt  interlocking  battery  in  the 
event  of  failure  of  the  commercial  power.  It  will  be  seen 
that  this  use  of  the  interlocking  battery  as  a  reserve  restricts 
the  lighting  to  operation  on  110  volts.  The  commercial  power 
may  be  either  alternating  or  direct  current  and  will  in  all 
probability  be  delivered  at  110  or  220  volts.  If  this  potential 
is  220  volts,  it  is,  of  course,  necessary  to  install  a  motor  gen- 
erator set,  transformer,  etc.,  to  reduce  the  voltage  to  that 
required  by  the  lighting  system. 

Where  a  reliable  source  of  alternating  current  is  available, 
such,  for  instance,  as  can  be  obtained  when  the  interlocking 
plant  is  located  in  A.  C.  automatic  signal  territory,  the  reserve 
battery  is  not  considered  necessary,  and  this  permits  the  light- 
ing system  to  be  operated  at  any  voltage  desired.  In  such  a 
case  low  voltage  metallic  filament  lamps  can  be  operated, 
transmission  about  the  plant  being  made  at  a  higher  voltage, 
thus  avoiding  the  necessity  of  installing  large  lighting  mains. 
In  this  connection  it  is  to  be  noted  that  low  voltage  lighting 
should  be  restricted  to  points  where  the  current  supply  is  abso- 


ELECTRIC   INTERLOCKING  HANDBOOK  129 

lutely  reliable,  except  in  the  case  of  a  plant  with  compara- 
tively few  signals,  at  which  plant  a  low  voltage  battery  of 
suitable  capacity  is  available  for  use  as  a  reserve. 

In  case  commercial  power,  of  the  proper  voltage,  or  sig- 
naling power  cannot  be  secured,  the  lights  should  then  be  oper- 
ated from  the  charging  generator,  provision  being  made  to 
transfer  the  lights  onto  the  interlocking  battery  in  case  of 
failure  of  the  generating  unit.  Attention  is  called  to  the 
undesirability  of  lighting  from  this  source  unless  either  the 
charging  unit  or  interlocking  battery  is  installed  in  duplicate, 
since  if  only  one  generator  and  one  battery  were  employed, 
the  capacity  of  the  battery  would  have  to  be  excessively 
large  to  provide  sufficient  reserve  against  the  failure  of  the 
charging  generator,  such  a  failure  in  all  probability  being  of 
longer  duration  than  would  be  the  case  with  commercial 
power. 

PRECAUTIONS 

In  operating  the  lighting  system  from  a  charging  generator 
great  care  should  be  used  to  see  that  the  normal  voltage  of  the 
lamj)s  is  never  exceeded,  since  the  bulbs  will  be  quickly  burnt 
out  if  subjected  to  an  excess  voltage.  This  increased  voltage 
always  exists  when  the  charging  generator  is  supplying  cur- 
rent for  the  lighting  system  at  the  same  time  it  is  charging  the 
interlocking  battery;  therefore,  a  regulating  device  must  be 
provided  to  maintain  the  voltage  on  the  lamps  at  the  normal 
point.  This  device  ordinarily  is  a  hand  operated  rheostat 
which  has  sufficient  regulation  to  permit  the  voltage  to  be 
kept  at  normal.  It  will  be  seen  that  the  device  will  require 
the  maintainer's  attention  at  frequent  intervals;  this,  how- 
ever, cannot  be  considered  serious,  as  under  such  conditions 
the  interlocking  battery  would  never  be  charged  at  night  except 
in  case  of  emergency.  Where  duplicate  batteries  are  employed, 
a  regulating  device  is  not  required,  as  the  combination  of 
switches  on  the  power  board  can  be  so  arranged  that  it  is 
impossible  to  serve  the  lighting  circuits  from  the  battery 
that  is  being  charged. 

Precaution  respecting  cross  protection  should  be  observed 
whenever  the  interlocking  battery  may  be  called  upon  to 
furnish  current  for  the  lighting  system.  At  plants  where  the 
operating  switchboard  is  equipped  with  the  cross  protection 
circuit  breaker  shown  in  Fig.  24  (both  positive  and  negative 
battery  connections  being  broken  through  the  circuit  breaker 
contacts),  the  signals  can  be  electrically  lighted  from  the  inter- 
locking battery  without  endangering  the  proper  operation  of 
the  switches,  signals,  or  other  functions  of  the  plant.  If, 
however,  it  is  proposed  to  electrically  light  the  signals  of  an 
existing  G.  R.  S.  plant  at  which  plant  the  old  type  of  circuit 
breaker  (Sec.  1,  Elec.  Int.  Cat.,  page  280)  is  installed,  it  is 
strongly  recommended  that  the  operating  switchboard  be 
equipped  with  the  double  pole  circuit  breaker  (Fig.  24)  and 
the  circuits  rearranged  to  embody  the  principles  of  the  wiring 


130  GENERAL  RAILWAY  SIGNAL  COMPANY 


shown  on  page  88.     The  lighting  mains  under  no  condition 
should  be  controlled  through  the  circuit  breaker. 

RECOMMENDATIONS 

It  is  recommended  that  two  bulbs  always  be  installed  in 
each  signal  lamp,  burning  in  multiple  or  operated  in  connec- 
tion with  a  "cut  in"  relay. 

Regarding  the  source  of  power,  it  is  recommended  as  good 
practice  that  commercial  power  be  employed,  providing 
arrangements  are  made  to  cut  the  lighting  system  onto  the 
interlocking  battery  in  case  of  failure  of  the  commercial  source. 

Where  the  interlocking  plant  is  located  in  A.  C.  automatic 
signal  territory  the  lighting  may  be  operated  on  any  voltage 
desired.  At  such  a  point  high  efficiency  metallic  filament 
lamps  can  readily  be  operated.  No  reserve  is  necessary,  in 
view  of  the  fact  that  the  signal  transmission  line  is  always 
thoroughly  protected  against  power  failure. 

Where  neither  commercial  power  nor  A.  C.  signaling  current 
is  available,  the  signal  lighting  may  be  electrically  operated 
from  the  charging  generator,  providing  the  interlocking  bat- 
tery is  (or  batteries  are)  of  sufficient  capacity  to  insure  the 
continuous  operation  of  the  interlocking  and  lighting  systems 
through  any  period  of  time  necessary  to  repair  a  failure  on  the 
part  of  the  charging  unit. 

In  all  cases  where  storage  batteries  may  be  called  upon  to 
furnish  current  for  the  lighting  circuits,  regulating  apparatus 
must  be  installed  to  permit  the  current  from  such  battery  to 
be  delivered  to  the  lighting  mains  at  normal  voltage  during  a 
charging  period. 

Whenever  the  interlocking  battery  serves  as  a  reserve,  the 
circuits  and  apparatus  on  the  operating  switchboard  must  be 
such  that  operation  of  the  lighting  system  will  in  no  way 
endanger  cross  protection. 


SECTION   V 


ELECTRIC    LOCKING   AND    CHECK    LOCKING 


GIVING  A  DESCRIPTION   OF  THE  VARI- 
OUS  TYPES    OF    CIRCUITS    AND    THEIR 
APPLICATION  TO  ELECTRIC    INTER- 
LOCKING  WORK 


E 


ELECTRIC  LOCKING 

LECTRIC  locking  as  defined  by  the  Railway  Signal  Asso- 
ciation consists  of  "the  combination  of  one  or  more  elec- 
tric locks  and  controlling  circuits  by  means  of  which 
levers  in  an  interlocking  machine,  or  switches  or  other  devices 
operated  in  connection  with  signaling  and  interlocking,  are 
secured  against  operation  under  certain  conditions." 

Electric  locking  is  a  development  of  the  tendency  in  rail- 
way signaling  practice  to  constantly  decrease  the  manual 
control  of  all  functions  and  to  increase  the  automatic  control. 
The  first  important  step  along  this  line  was  the  operation  of 
switches  and  signals  through  the  medium  of  interlocked  levers 
concentrated  in  a  central  machine.  The  real  beginning  of 
electric  locking,  however,  was  in  the  installation  at  mechani- 
cal plants  of  locking  circuits  which  were  to  prevent  the  lever- 
man  from  changing  the  route  in  the  face  of  an  approaching 
train.  This  was  followed  by  a  step  which  had  its  inception  in 
the  all-electric  interlocking  system :  namely,  section  or  detector 
locking  which  was  designed  to  afford  safety  to  a  train  from 
the  time  it  passed  the  home  signal  location  until  it  cleared 
the  limits  of  the  interlocking  plant.  As  first  installed  in  con- 
nection with  electric  interlocking,  the  switches  and  derails  in 
a  given  track  section  were  prevented  from  being  thrown  while 
a  train  was  on  that  track  section,  by  interrupting  the  current 
supply  to  those  functions  by  means  of  a  relay  controlled  by 
the  track  relay  of  the  section  in  question.  At  the  present 
time  this  method  of  control  is  not  generally  used  with  the 
all-electric  system,  having  given  way  to  the  practice  of  equip- 
ping each  switch  and  derail  lever  with  electric  locks,  properly 
controlled  by  the  various  track  sections. 

Ever  since  the  time  of  those  first  successful  installations, 
the  signal  men  of  the  country  have  become  more  and  more 
alive  to  the  fact  that  safety  of  railway  operation  could  be 
much  further  assured  by  the  development  of  this  principle  of 
automatically  preventing  the  operation  of  functions  which 
might  endanger  the  safety  of  trains  approaching  or  passing 
through  interlocking  plants.  In  fact,  at  the  present  time 
electric  locking  has  come  to  be  considered  by  many  a  necessary 
adjunct  to  an  interlocking  plant. 

Due  to  the  rapidity  of  the  development  of  the  art,  a  wide 
range  of  methods  has  been  used  to  accomplish  the  same 
result;  the  principles  involved,  nevertheless,  have  been  so 
nearly  uniform  that  it  has  become  possible  to  determine  the 
elements  that  enter  into  good  practice.  For  instance,  it  will 
be  found  that  it  should  always  be  possible  to  restore  the  home 
signal  to  the  normal  position,  even  though  it  may  not  be 
desirable  to  release  the  route  beyond.  Also  in  case  of  emerg- 
ency, release  of  the  route  is  generally  permitted  through  the 
use  of  a  time  release  or  hand  switch;  the  circuits  are  such 
that  when  the  device  has  been  operated  to  secure  the  desired 


134 


GENERAL  RAILWAY  SIGNAL  COMPANY 


FIG.  96.     ELECTRIC  TIME  RELEASE 

release,  some  circuit  essential  to  the  operation  of  either  switch 
or  signal  functions  will  be  broken,  thus  necessitating  that  the 
time  release  or  hand  switch  be  returned  to  its  normal  position 
before  operation  of  the  switches  or  signals  affected  can  be 
resumed. 

Based  on  the  above,  the  Railway  Signal  Association  has 
classified  Electric  Locking  in  the  following  manner: 
"SECTION  LOCKING.  Electric  locking  effective  while  a  train 
occupies  a  given  section  of  a  route  and  adapted  to  prevent 
manipulation  of  levers  that  would  endanger  the  train  while 
it  is  within  that  section." 

An  illustration  of  section  locking  is  given  in  Fig.  97,  showing 
the  manner  of  controlling  the  locks  with  which  the  switch 
levers  are  equipped.  As  the  levers  are  locked  in  either  the 
full  normal  or  full  reverse  position,  it  will  be  seen  that  the 


./O^1 ^*"     f  i -^i U*— 

^    7itZ^C 


on  Achievers 

FIG.  97.     SECTION  LOCKING  CIRCUIT 


ELECTRIC   INTERLOCKING   HANDBOOK 


135 


operator  is  prevented  from  changing  the  position  of  the  switches 
or  derails  in  a  given  section  during  such  time  as  that  section 
is  occupied  or  fouled  by  a  train. 

"  ROUTE  LOCKING.  Electric  locking  taking  effect  when  a  train 
passes  a  signal  and  adapted  to  prevent  manipulation  of  levers 
that  would  endanger  the  train  while  it  is  within  the  limits 
of  the  route  entered." 

Route  locking  is  a  development  of  section  locking  in  which 
the  switches  and  derails  in  all  sections  of  any  route  are  locked 


\l 


Repeating 
relay  for 
Section  IZT 


Full  normal  and 
reverse  lock  on 
switch  lever  '  1 1 


Repeating 
relay  for  - 
Section  UT  + 


Full  normal  and 
reverse  lock  on 
switch  lever  14 


FIG.  98.     ROUTE  LOCKING  CIRCUIT 

NOTE. —  To  positive  battery  through  lever  contacts  and  relays  as  de- 
termined by  the  layout  of  track  indicated  by  dotted  lines. 

from  the  time  a  train  enters  that  route  until  such  time  as  the 
route  is  cleared.  An  illustration  of  route  locking  applied  to 
a  simple  layout  is  shown  in  Fig.  98.  It  is  evident  that  the 
circuits  become  somewhat  complicated  when  used  in  connec- 
tion with  an  interlocking  where  the  routing  of  each  signal 
may  extend  over  a  number  of  combinations  of  track  sections. 
"SECTIONAL  ROUTE  LOCKING.  Route  locking  so  arranged  that 
a  train,  in  clearing  each  section  of  the  route,  releases  the  locking 
affecting  that  section." 

This  is  a  further  development  of  section  locking  in  which 
the  functions  in  all  sections  in  a  given  route  are  locked  as 


136  GENERAL  RAILWAY  SIGNAL  COMPANY 


soon  as  the  train  has  passed  the  home  signal,  the  functions  in 
each  section,  however,  being  released  behind  the  train  as  soon 
as  the  train  has  passed  out  of  the  section. 

The  installation  of  sectional  route  locking  has  been  largely 
restricted  to  points  such  as  congested  terminals  where  the 
maximum  number  of  traffic  movements  is  demanded  with  a 
maximum  of  protection.  Due  to  its  being  little  used,  and  on 
account  of  the  rather  complicated  circuits  involved,  no  at- 
tempt has  been  made  to  show  any  typical  illustration  of  the 
circuits  required  in  such  work. 


Control  5ig.6 

"  Half  reverse  lock 

Screw  Release  £*     on  5ign<al  lever  6 


FIQ.  99.     APPROACH  LOCKING  CIRCUIT 

"APPROACH  LOCKING.  Electric  locking  effective  while  a  train 
is  approaching  a  signal  that  has  been  set  for  it  to  proceed  and 
adapted  to  prevent  manipulation  of  levers  or  devices  that 
would  endanger  that  train." 

Fig.  99  shows  an  approach  locking  circuit  in  which  a  half 
reverse  lock  on  the  home  signal  lever,  through  the  medium  of 
the  locking  between  the  signal  and  switch  levers,  prevents  the 
release  of  the  route  during  such  time  as  the  lock  is  de-energized. 
The  locking  becomes  effective  after  the  signal  for  the  route  has 
been  cleared  and  the  train  has  passed  a  predetermined  point, 
which  in  Fig.  99  is  the  annunciator  section;  the  locking  is 
released  as  soon  as  the  train  passes  the  home  signal. 

It  will  be  noted  that  in  Fig.  99  no  protection  is  given  after 
the  train  has  passed  the  home  signal,  i.  e.  —  no  route  locking 
protection  is  afforded.  Protection  can  be  given  through  the 
plant  by  releasing  the  signal  lever  in  the  first  section  beyond 
the  limits  of  the  plant  instead  of  on  the  forty-five  degree 
control  relay. 


ELECTRIC   INTERLOCKING  HANDBOOK  137 


"STICK  LOCKING.  Electric  locking  taking  effect  upon  the 
setting  of  a  signal  for  a  train  to  proceed,  released  by  a  passing 
train,  and  adapted  to  prevent  manipulation  of  levers  that 
would  endanger  an  approaching  train." 

Stick  locking  in  reality  is  only  another  form  of  approach 
locking,  being  different  in  that  it  becomes  effectve  on  the 
reversal  of  the  home  signal  lever  and  does  not  further  depend 
on  the  approach  of  a  train. 

Fig.  100  shows  a  stick  locking  circuit  in  which  the  half  reverse 
lock,  with  which  the  signal  lever  is  equipped,  prevents  its 
return  to  the  full  normal  position,  and,  therefore,  the  release 
of  the  route  governed,  until  such  time  as  a  train  has  passed  on 
to  the  release  section  ;  this  section  is  shown  located  beyond  the 
interlocking  limits  as  mentioned  under  "Approach  Locking." 


L  . 

Ir"  li 


Screw  Relea 
Control 


FIG.  100.     STICK  LOCKING  CIRCUIT 

It  will  be  seen  that  it  is  necessary  to  restore  the  signal  lever  to 
the  normal  position  while  the  train  is  on  the  releasing  section, 
otherwise  the  signal  lever  can  only  be  returned  to  the  full 
normal  position  through  the  operation  of  the  time  release. 
If  desired,  the  releasing  section  may  be  extended  to  include 
the  several  track  sections  in  the  route  so  that  the  lever  may 
be  restored  to  the  normal  position  any  time  the  train  is  within 
the  limits  of  the  route. 

"INDICATION  LOCKING.  Electric  locking  adapted  to  prevent 
any  manipulation  of  levers  that  would  bring  about  an  unsafe 
condition  in  case  a  signal,  switch,  or  other  operated  device  fails 
to  make  a  movement  corresponding  with  that  of  the  operating 
lever ;  or  adapted  directly  to  prevent  the  operation  of  one  de- 
vice in  case  another  device,  to  be  operated  first,  fails  to  make 
the  required  movement." 

As  an  illustration  of  this  type  of  locking  may  be  taken 
any  electrical  device,  which  is  designed  to  indicate  the  cor- 
respondence of  position  between  a  unit  and  its  controlling 


138 


GENERAL  RAILWAY  SIGNAL  COMPANY 


lever.  The  simplest  example  is  the  indication  of  the  position 
of  a  semaphore  blade  by  means  of  a  lock  or  other  device  on 
the  governing  lever,  the  control  of  this  lock  being  carried 
through  the  circuit  breaker  on  the  signal.  The  well-known 
dynamic  indication  of  the  all-electric  system  is  a  striking 
example  of  indication  locking. 

It  will  be  found  that  with  the  exception  of  certain  forms  of 
indication  locking,  such  as  the  dynamic  indication,  the  differ- 
ent basic  forms  of  electric  locking  as  outlined  above  are  seldom 
used  alone,  but  in  combinations. 


TK 

M2' 

^d_T  j[  Annunciator 


Screw  Release    f 


Full  Normal  and  Reverse 
lochs  on  Switch  Levers. 

FIG.  101.     CIRCUITS  FOR  COMBINATION  OF  APPROACH,  INDICATION 
AND  SECTION  LOCKING 


Fig.  101  illustrates  the  use  of  an  approach  locking  circuit  in 
conjunction  with  section  locking,  and  with  indication  locking 
for  distant  signal  No.  1.  In  this  circuit  the  control  is  secured 
by  equipping  the  switch  levers  with  electric  locks  governed  by 
a  stick  relay.  The  locking  becomes  effective  when  signal 
No.  6  is  cleared  but  is  capable  of  being  released  by  the  return 
of  lever  No.  6  to  the  normal  position,  providing  a  train  has 
passed  into  the  releasing  section,  or  providing  no  train  is  on 
any  of  the  track  sections  repeated  by  the  annunciator  and 
the  forty-five  degree  control  relay  for  signal  No.  6.  This 
circuit  does  not  require  that  the  lever  be  returned  to  the 
normal  position  while  the  train  is  on  the  releasing  section. 


ELECTRIC   INTERLOCKING   HANDBOOK 


139 


If  this  feature  is  desired  the  control  may  be  broken  through 
the  contacts  on  lever  No.  6  instead  of  through  the  circuit 
breaker  of  the  signal. 

The  indication  locking  feature  consists  of  carrying  the 
control  of  the  stick  relay  through  the  circuit  breaker  of  dis- 
tant signal  No.  1  to  prevent  release  of  the  route  under  any 
condition  if  signal  No.  1  is  not  in  the  caution  or  stop  position. 

Fig.  102  illustrates  a  similar  arrangement  of  tracks  and  sig- 
nals, with  circuits  providing  stick  locking,  section  locking,  and 
indication  locking.  It  is  to  be  noted  that  in  every  particular 


^^ 


rae       ^i 
10 -IF— i    ^— ? 


Stick  Relay 


Full  Normal  and  Reverse 
locks  on  Switch  Levers 

FIG.  102.     CIRCUIT  FOR  COMBINATION  OF  STICK,  INDICATION  AND 
SECTION  LOCKING 

this  circuit  is  the  same  as  that  in  Fig.  101,  except  that  the  stick 
relay  does  not  have  a  pick  up  through  the  forty-five 
degree  control  relay  and  the  annunciator  in  series;  the 
omission  of  this  wire  classes  the  circuit  under  "Stick  Locking." 
The  locking  becomes  effective  upon  the  clearing  of  signal 
No.  6  and  is  released  by  a  train  on  the  clearing  section  or  by 
operation  of  the  time  release. 


CHECK   LOCKING 

WHEN  interlocking  plants  are  located  a  comparatively 
short  distance  apart,  it  is  advisable  and  frequently 
necessary  to  install  what  is  known  as  "Check  Lock- 
ing," which  enforces  cooperation  between  the  levermen  at  the 
two  plants  in  such  a  manner  as  to  prevent  opposing  signals, 
governing  over  the  same  track,  from  being  at  proceed  at  the 
same  time.     Furthermore,  after  a  signal  has  been  cleared  and 
accepted  by  a  train,  check  locking  prevents  an  opposing  signal 
at  the  adjacent  interlocking  plant  from  being  cleared  until  the 
train  has  passed  through  to  that  plant. 

Fig.  103  shows  a  check  locking  circuit  which  involves  the 
use  of  check  lock  levers  at  each  plant,  the  arrangement  and 
method  of  operation  of  these  levers  making  the  circuit  especially 


z  Q 


RgQ   . 


FIG.  103.     CHECK  LOCKING  CIRCUIT 
For  use  where  there  is  no  preference  as  to  direction  cf  traffic. 

adaptable  where  there  is  no  preference  as  to  the  direction  of 
traffic.  The  signal  levers  at  each  station,  governing  move- 
ments over  the  intervening  track,  are  so  interlocked  with  the 
check  lock  levers  in  their  respective  machines,  that  they  may 
not  be  moved  from  their  full  normal  position  until  their  re- 
spective check  lock  levers  have  been  moved  to  the  full  reverse 
position.  By  reference  to  Fig.  103  it  will  be  seen  that  the 
check  lock  levers  are  so  controlled  that  but  one  of  them  can 
be  in  the  full  reverse  position  at  the  same  time.  Therefore, 
it  is  impossible  for  signals  No.  1  and  No.  20  at  stations  A  and 
Z,  respectively,  to  be  displayed  at  proceed  at  the  same  time. 

The  control  circuit  for  the  check  lock  levers  is  shown  broken 
through  relay  X,  which  represents  the  track  relays  for  the 
sections  between  signals  No.  1  and  No.  20.  This  prevents  a 
check  lock  lever  being  thrown  to  the  full  reverse  position 
and,  consequently,  any  traffic  movement  from  being  made 
during  such  time  as  these  sections  are  occupied.  The  release 


ELECTRIC   INTERLOCKING   HANDBOOK 


141 


of  either  lever  in  moving  to  the  reverse  position  is  effected 
by  current  taken  from  the  battery  at  the  far  end  of  the  circuit. 

The  check  locking  circuit  shown  in  Fig.  104  is  designed  for 
operation  when  there  is  a  preference  in  the  direction  of  traffic, 
since  traffic  movements  can  normally  be  made  from  A  to  Z 
without  any  interference  from  the  check  locking,  it  being 
necessary,  however,  when  making  a  movement  from  Z  to  A 
(against  traffic)  to  operate  both  check  lock  levers. 

Each  station  is  equipped  with  a  check  lock  lever  so  interlocked 
with  signal  levers  No.  1  and  No.  20,  that  lever  No.  1  is 
free  to  be  moved  only  when  the  check  lock  lever  at  A  is  full 
normal,  and  lever  No.  20  only  when  the  check  lock  lever 
at  Z  is  full  reverse.  The  control,  however,  of  the  check 
lock  levers  is  such  that  the  lever  at  Z  can  be  reversed  only 

II.,  z  Q          £0 IL- 


KXCATKM,  MA«MCT 


FIG.  104.     CHECK  LOCKING  CIRCUIT 
For  use  where  there  is  preference  as  to  direction  of  traffic. 

after  the  check  lock  lever  at  A  has  been  thrown  to  the  full 
reverse  position,  and,  after  having  been  moved  from  its  normal 
position,  the  lever  at  A  can  be  returned  to  the  full  normal 
position  only  after  the  return  of  the  check  lock  lever  at  Z  to 
full  normal.  Thus  it  will  be  seen  that  it  is  impossible  to  have 
a  condition  existing  which  would  permit  signal  levers  No.  1 
and  No.  20  to  be  reversed  at  the  same  time. 

The  final  movement  of  the  check  lock  lever  at  Z  in  being 
moved  to  the  full  reverse  position,  and  of  the  check  lock  lever 
at  A  in  being  placed  normal,  is  permitted  by  energy  secured 
from  the  battery  located  at  the  far  end  of  the  circuit. 


SECTION  VI 


INSTALLATION  AND  OPERATING  DATA  FOR 
POWER    PLANTS   AND    SWITCHBOARDS 


COVERING  LEAD  TYPE  STORAGE  BAT- 
TERIES, GENERATORS  AND  MOTOR 
GENERATORS,  GASOLINE  ENGINES  AND 
SWITCHBOARDS,  WITH  DATA  AND 
TABLES  FOR  THE  DETERMINATION  OF 
THE  PROPER  TYPE  AND  CAPACITIES 
OF  APPARATUS 


LEAD  TYPE  STORAGE  BATTERIES 

STORAGE  or  secondary;  batteries  consist  of  cells,  the  plates 
and  electrolyte  of  which  can  be  restored  to  their  original 
condition  after  discharge,  by  forcing  an  electric  current 
through  the  cell  in  the  direction  opposite  to  that  taken  by 
the  current  produced  by  the  cell.     When  a  primary  battery 
is  exhausted  the  electrolyte  and  elements  are  renewed  before 
further  use.     It  is  in  this  reversability  or  regeneration  that 
lies  the  fundamental  difference  between  storage  and  primary 
cells. 

The  lead  type  storage  cell  consists  essentially  of  two 
plates  or  sets  of  plates  suspended  in  a  dilute  solution  of  sul- 
phuric acid.  There  are  many  forms  of  plate  construction,  but 
the  chemical  composition  is  generally  the  same,  the  positive 
and  negative  plates  being  made  of  peroxide  of  lead  and  pure 


FIG.  105   LEAD  TYPE  STORAGE  BATTERY  AND  BATTERY  RACK 

or  "sponge"  lead,  respectively.  When  the  elements  are  com- 
posed of  more  than  two  plates  the  negative  plates  in  each 
cell  are  one  more  in  number  than  the  positives.  Wooden 
or  hard  rubber  separators  are  introduced  between  the  plates 
to  prevent  any  of  the  positives  from  coming  into  contact  with 
the  negative  plates,  thus  causing  short  circuit. 

When  the  circuit  is  closed  and  the  battery  discharging,  the 
sulphuric  acid  combines  with  the  lead  in  the  elements  forming 
a  deposit  of  sulphate  of  lead  on  the  surface  of  both  positive 
and  negative  plates,  the  density  (specific  gravity)  of  the 
electrolyte  diminishing  as  the  sulphuric  acid  leaves  it  to  com- 
bine with  the  materials  of  the  plates.  By  forcing  current 
through  the  cell  in  the  direction  opposite  to  that  of  the  dis- 
charged current,  the  sulphate  of  lead  on  the  negative  plates 
will  be  converted  into  sponge  lead  and  sulphuric  acid,  and  the 
sulphate  of  lead  in  the  positive  plates  into  peroxide  of  lead 
and  sulphuric  acid ;  the  sponge  lead  and  the  peroxide  of  lead 
remain  in  the  plates  and  the  sulphuric  acid  diffuses  in  the 
electrolyte,  the  specific  gravity  of  which  rises  in  consequence. 


146 


GENERAL  RAILWAY   SIGNAL  COMPANY 


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ELECTRIC  INTERLOCKING  HANDBOOK  147 

EXTRACT  FROM  R.  S.  A.  SPECIFICATIONS    FOR 
LEAD  TYPE  STATIONARY  STORAGE  BAT- 
TERY FOR  INTERLOCKINGS  (1913) 

1.  INTENT 

The  intent  of  these  specifications  is  to  provide  for  the 
furnishing  of  complete  storage  battery  cells  and  parts, 
designed  to  be  located  in  interlocking  stations  or  battery- 
houses  and  used  for  operating  interlocking  and  signal 
apparatus. 

2.  DESIGNATIONS 

(a)  In  ordering  cells  or  parts  the  nominal  capacity  re- 
quired will  be  designated  as  "40  A.  H.,  "80  A.  H.,"  "120 
A.  H.,"  "200  A.  H.,"  "320  A.  H.,"  or  "400  A.  H.,"  and 
these  terms  shall  be  understood  to  signify,  on  an  eight  (8) 
hour  basis,  the  capacities  and  dimensions  thus  designated 
in   these   specifications  and   Railway   Signal   Association 
drawing  1224.     (See  page  146.) 

(b)  Each  complete  cell,  unless  otherwise  specified,  is 
understood  to  include  the  following  parts : 

1.  One  (1)  positive  group,  consisting  of  the  neces- 
sary number  of  positive  plates  assembled  with  con- 
necting strap  and  one  (1)  connecting  bolt. 

2.  One  (1)  negative  group,  consisting  of  the  neces- 
sary number  of  negative  plates  assembled  with  con- 
necting strap  and  one  (1)  connecting  bolt. 

3.  One  (1)  set  of  separators,  with  dowels  and  hold 
downs. 

4.  One  (1)  glass  jar. 

5.  One  (1)  glass  sand  tray,  with  moulded  feet. 

6.  One  (1)  glass  cell  cover. 

7.  Required  electrolyte. 

(c)  Positive  or  negative  groups,  if  ordered  separately, 
will  be  ready  for  service  after  an  initial  charge  continued 
for  fifty  (50)  to  sixty  (60)  hours  at  the  eight  (8)  hour  rate. 

3.  CAPACITY  OP  BATTERY 

In  conformity  with  service  requirements. 

4.  NUMBER  OP  CELLS  PER  BATTERY 

In  conformity  with  voltage  requirements. 

5.  DIMENSIONS 

Jars,  sand  trays  and  covers  must  conform  to  Railway 
Signal  Association  drawing  1224,  which  is  an  essential 
part  of  these  specifications.  (See  page  146.) 

6.  ELEMENTS 

(a)  Positive  plates  shall  be  of  the  Plante  type. 


148  GENERAL  RAILWAY  SIGNAL  COMPANY 


(&)  Negative  plates  shall  be  either  of  the  Plante  type  or 
of  the  type  having  mechanically  applied  active  material. 

(c)  Positive  and  negative  plates  shall  be  respectively 
connected  into  positive  and  negative  groups  by  burning  to 
lead  straps. 

7.  SEPARATORS 

Separators  shall  be  of  specially  treated  wood. 

8.  ELECTROLYTE 

(a)  Electrolyte  shall  have  a  specific  gravity  of  between 
1.205  and  1.215  at  the  end  of  the  initial  charge  in  service. 

(6)  Electrolyte  shall  be  in  accordance  with  Railway 
Signal  Association  specifications. 

9.  ACCEPTANCE 

No  unit  or  part  will  be  accepted  which  does  not,  in  the 
judgment  of  the  Purchaser,  conform  to  the  best  practice 
with  respect  to  material  and  workmanship. 

10.  SERVICE  REQUIREMENTS 

(a)  It  is  essential  that  all  parts  shall  be  rugged  in  the 
highest  degree  both  mechanically  and  electrically.  The 
apparatus  furnished  must  give  satisfactory  and  economical 
service. 

(6)  Should  any  injurious  buckling  of  plates  occur  in 
normal  service  within  one  (1)  year  after  delivery,  or 
should  the  capacity  of  any  cell  or  element  fall  to  less  than 
eighty-five  (85)  per  cent,  of  the  specified  capacity  at  the 
eight  (8)  A.  H.  rate,  in  normal  service,  within  one  (1) 
year  after  delivery,  the  Contractor  must  replace  the 
defective  parts  and  restore  the  affected  cells  to  their  full 
specified  capacity  and  to  a  condition  satisfactory  to  the 
Purchaser,  without  additional  cost  to  him. 

(c)  As  far  as  practicable,  it  is  understood  that  the  cells 
are  to  be  operated  in  the  manner  recommended  by  the 
Contractor,  but  the  necessities  of  operation  must  be  the 
first  consideration. 


R.  S.  A.  DIRECTIONS   FOR   INSTALLATION   OF 
LEAD   TYPE   STATIONARY  STORAGE 

BATTERIES  (1909) 
1.    GENERAL 

(a)  The  battery  should  be  housed  in  a  space  by  itself  as 
the  acid  fumes  given  off  during  the  charge  are  of  a  cor- 
rosive nature.  This  space  should  be  well  ventilated, 
well  lighted,  and  as  dry  as  possible.  If  the  space  is  speci- 
ally constructed  it  should  contain  no  metal  work  other 
than  lead.  If  this  is  not  possible,  then  such  metal  parts 


ELECTRIC  INTERLOCKING   HANDBOOK  149 


should  be  protected  by  at  least  two  (2)  coats  of  acid-proof 
paint.  The  floors  of  a  large  battery  room  should  be 
preferably  of  vitrified  brick,  jointed  with  pitch. 

(6)  Batteries  should  be  placed  in  a  room  having  a  uni- 
form temperature,  preferably  seventy  (70)  degrees  Fahr. 
Low  temperature  does  not  injure  a  battery,  but  lowers  its 
capacity  approximately  one-half  (%)  of  one  per  cent,  per 
degree.  Excessively  high  temperatures  shorten  the  life  of 
the  plates. 

(c)  If  glass  jars  are  used  and  cell  is  not  of  the  two-plate 
type,  the  following  should  be  observed : 

1.  Batteries  up  to  four  hundred  (400)  ampere  hour 
capacity  shall  be  placed  in  glass  jars. 

2.  The  capacity  of  batteries  shall  'be  for  an  eight 
(8)  hour  rate  of  discharge  at  seventy  (70)  degrees  Fanr. 

3.  Batteries  having  a  large  number  of  cells,  such  as 
at    interlocking  plants,   shall   be    provided   with    sub- 
stantial wood  racks  to  support  them.     These  racks  shall 
preferably  be  made  of  long-leaf  yellow  pine  with  non- 
corrosive  fastenings,  and  thoroughly  protected   by  at 
least  two  (2)  coats  of  acid-proof  paint.     Cells  shall  be 
arranged  transversely,  and  the  layouts  be  such  that 
each  cell  is  accessible  for  inspection  and  provide  suf- 
ficient head  room  over  each  cell  to  remove  the  element 
without  moving  the  jar. 

4.  Each  jar  shall  be  set  in  a  tray  which  has  been 
evenly  filled  with  fine  dry  bar  sand,  the  trays  resting  on 
suitable  insulators. 

5.  When  placing  the  positive  and  negative  groups 
into  the  jars  see  that  the  direction  of  the  lug  is  rela- 
tively the  same  in  each  case,  so  that  a  positive  lug  of 
one  (1)  cell  adjoins  and  is  connected  to  a  negative  lug  of 
the  next  cell  throughput  the  battery,  thereby  giving 
proper  polarity,  providing  a  positive  lug  at  one  free  end 
and  a  negative  at  the  other. 

6.  Before  bolting  the  battery  lugs  together,  they 
should  be  well  scraped  at  the  point  of  contact,  to  insure 
good  conductivity  and  low  resistance  in  the  circuit.     The 
connector  studs  should  be  covered  with  vaseline  before 
screwing  up,  and  all  connections  covered  with  vaseline 
or  suitable  paint. 

7.  Before  putting  electrolyte  in  the  battery  the  cir- 
cuits connecting  same  with  the  charging  source  must  be 
completed,  care  being  taken  to  have  the  positive  pole  of 
the  charging  source  connected  with  the  positive  end  of 
the  battery  and  the  negative  poles.     The  electrolyte 
should  cover  the  top  of  plates  by  one-half  (%)  inch. 

2.  ELECTROLYTE 

(a)  The  electrolyte  must  be  free  from  impurities  and 
meet  the  tests  prescribed  by  the  Railway  Signal  Association. 


150  GENERAL  RAILWAY  SIGNAL  COMPANY 


INITIAL  CHARGE 

(a)  The  initial  charge  must  follow  the  Manufacturer's 
instructions.  The  charge  should  be  started  promptly  as 
soon  as  all  the  cells  are  filled  with  electrolyte,  and  all  con- 
nections made,  usually  at  the  normal  rate,  and  continued 
at  the  same  rate  until  both  the  specific  gravity  and  voltage 
show  no  rise  over  a  period  of  ten  (10)  hours,  and  gas  is 
being  freely  given  off  from  all  the  plates.  The  positive 
plates  will  sometimes  gas  before  the  negatives.  Gen- 
erally, to  meet  these  conditions,  from  forty-five  (45)  to 
fifty-five  (55)  hours  continuous  charging  at  the  normal 
rate  will  be  required;  and  if  the  rate  is  less,  the  time 
required  will  be  proportionately  increased.  In  case  the 
charge  is  interrupted,  particularly  during  its  earlier  stages, 
or  if  it  is  not  started  as  soon  as  the  electrolyte  is  in  the 
cells,  the  total  charge  required  (in  ampere  hours)  will  be 
greater  than  if  the  charge  is  continued  and  is  started  at  once. 

(6)  As  a  guide  in  following  the  progress  of  the  charge, 
readings  should  be  regularly  taken  and  recorded.  The 
gassing  should  also  be  watched,  and  if  any  cells  are  not 
gassing  as  much  as  the  adjoining  cells,  they  should  be 
carefully  examined  and  the  cause  of  the  trouble  removed. 
The  temperature  of  the  electrolyte  should  be  closely 
watched,  and  if  it  approaches  one  hundred  (100)  degrees 
Fahr.  the  charging  rate  must  be  reduced  or  the  charge 
temporarily  stopped  until  the  temperature  lowers. 

(c)  The  specific  gravity  will  fall  after  the  electrolyte  is 
added  to  the  cells,  and  will  then  gradually  rise  as  the 
charge  progresses,  until  it  is  up  to  1.210  or  thereabout. 

(d)  The  voltage  of  each  cell  at  the  end  of  the  charge 
will  have  risen  to  its  maximum  and  usually  will  be  be- 
tween two  and  five-tenths  (2.5)  and  two  and  seven-tenths 
(2.7)  volts. 

(e)  If  the  specific  gravity  of  any  of  the  cells  at  the  com- 
pletion of  the  charge  is  below  1.205,  or  above  1.215,  allow- 
ance being  made  for  the  temperature  correction,  it  should 
be  adjusted  to  within  these  limits,  by  removing  and  adding 
electrolyte  if  the  specific  gravity  is  low,  and  adding  chemi- 
cally pure  water  if  the  specific  gravity  is  high,  to  again 
bring  the  surface  at  the  proper  height  above  the  top  of 
the   plates.     It  is   of   the  utmost   importance  that  the 
initial  charge  be  complete  in  every  respect. 

(/)  In  case  of  batteries  charging  from  primary  cells,  if 
possible,  the  initial  charge  should  be  given  at  a  place 
where  direct  current  is  available  of  sufficient  voltage  to 
complete  the  charge  at  the  normal  rate,  the  cells  being 
then  transferred  to  their  permanent  position. 

TWO-PLATE  CELLS 

The  general  method  of  installation  is  the  same  as  the 
above  with  the  following  exceptions:  Each  cell  contains 


ELECTRIC  INTERLOCKING   HANDBOOK  151 


one  positive  and  one  negative  plate,  the  positive  of  one 
cell  being  solidly  connected  by  a  lead  strap  to  the  nega- 
tive plate  of  the  adjoining  cell,  and  consequently  no  con- 
nectors are  required.  At  the  ends  of  each  row  there  is 
one  (1)  free  positive  plate  and  one  (1)  free  negative  plate 
respectively,  which  constitute  the  positive  and  negative 
terminals  of  that  row.  Connections  to  these  terminals  are 
made  with  bolt  connectors. 

5.    LARGE  CAPACITY  CELLS 

(a)  Batteries  of  a  greater  capacity  than  four  hundred 
(400)  ampere  hours  shall  be  placed  in  wood  tanks  and  shall 
be  covered  by  special  specifications. 

(6)  Where  tanks  are  used,  it  is  customary  to  support 
them  on  a  double  tier  of  glass  insulators. 

(c)  Plates  are  shipped  separately  and  assembled  one  at 
a  time  in  the  tank  and  burned  solidly  to  a  heavy  lead  bus 
bar  by  means  of  a  hydrogen  flame.  It  is  recommended 
that  when  installations  of  this  kind  are  required  that 
battery  Manufacturers  install  the  battery  in  accordance 
with  tneir  standard  practice. 


R.  S.  A.  INSTRUCTIONS   FOR   OPERATION   OF  LEAD 
TYPE   STORAGE   BATTERIES  AT  INTER- 
LOCKING  PLANTS  (1909) 

1.  BATTERY 

batteries ; cells  each ;  type ;  number  of 

plates  per  cell normal  charging  rate amperes. 

batteries; cells  each;  type ;  number  of 

plates  per  cell normal  charging  rate amperes. 

2.  PILOT  CELL 

In  each  battery,  select  a  readily  accessible  cell,  to  be 
used  in  following  the  daily  operation  of  the  battery,  by 
taking  specific  gravity  readings  of  the  electrolyte,  as 
given  below.  Keep  the  level  of  the  electrolyte  of  this  cell 
at  a  fixed  height,  one-half  (x/2)  inch  above  the  top  of  the 
plates,  by  adding  a  small  quantity  of  chemically  pure 
water  each  day;  THIS  is  EXTREMELY  IMPORTANT. 

3.  CHARGING 

(a)  When  to  charge. 

1.  As  a  general  rule,  do  not  charge  until  the  specific 
gravity  of  the  pilot  cell  has  fallen  at  least  ten  (10)  points 
below  the  preceding  overcharge  maximum,  the  battery 
being  then  about  one-third  (Vs)  discharged. 

2.  In  any  case,  charge  as  soon  as  possible  after  reach- 
ing either  of  the  limits  given  below  under  "Discharging," 
or  if  for  any  reason  a  heavy  discharge  is  expected. 


152  GENERAL  RAILWAY  SIGNAL  COMPANY 


(6)  Regular  charge. 

1.  Charge  at  normal  rate  of   ........  amperes,  or  as 

near  as  possible,  and  continue  until  the  specific  gravity  of 
the  pilot  cell  has  risen  to  three  (3)  points  below  the  maxi- 
mum reached  on  the  preceding  overcharge,  WHEN  THE 
CHARGE  SHOULD  BE  STOPPED  :  for  example,  if  the  maxi- 
mum specific  gravity  on  the  overcharge  is  1.207,  the  spe- 
cific gravity  reached  on  regular  charge  should  be  1.204. 

2.  The  cells  should  all  be  gassing  moderately. 

(c)  Overcharge. 

1.  Once  every  two  (2)  weeks,  on  .................. 

prolong  the  regular  charge  until  fifteen  (15)  minute  read- 
ings of  the  specific  gravity  of  the  pilot  cell  and  of  the 
battery  voltage,  taken  from  the  time  the  cells  commence 
to  gas  show  no  rise  on  five  (5)  successive  readings,  thus 
having  been  at  a  maximum  for  one  hour. 

2.  When  the  above  method  of  overcharge  is  not  prac- 
ticable, the  overcharge  may  be  given  every  sixth  charge, 
provided  the  battery  receives  an  overcharge  at  least  once 
every  month.     If  in  following  this  method,  i.  e.,  where 
the  overcharge  is  given  at  intervals  longer  than  two  (2) 
weeks  and  not  less  frequently  than  once  a  month,  the 
regular   charge  should  be  prolonged  until  one-half  (¥2) 
hour  readings  of  the  specific  gravity  of  the  pilot  cell  and 
of  the  battery  voltage,  taken  from  the  time  trie  cells  begin 
to  gas,  show  no  rise  on  seven  (7)  successive  readings,  thus 
having  been  at  the  maximum  for  three  (3)  hours. 

3.  The  cells  should  all  be  gassing  freely. 

4.  The  overcharge  should  be  given  whether  the  bat- 
tery has  been  in  regular  use  or  not. 

(d)  Charging  in  series. 

If  two  (2)  or  more  batteries  are  charged  together,  in 
series,  care  should  be  taken  that  each  battery  is  cut  out 
when  fully  charged  ;  in  other  words,  if  one  of  the  batteries 
discharges  less  than  the  other  it  should  not  receive  the 
same  charge. 

4.    DISCHARGING 

(a)  Never  allow  the  specific  gravity  of  the  pilot  cell  to 
fall  more  than  about  thirty  (30)  points  below  the  preceding 
overcharge  maximum.  As  a  rule,  do  not  allow  specific 
gravity  to  fall  more  than  twenty  (20)  points. 

(6)  Never   allow   the   voltage   to   go   below   ONE   AND 

EIGHTY-FIVE    ONE-HUNDREDTH3     (1.85)     VOLTS    PER    CELL 

when  discharging  at  the  normal  rate  (  ..........  amperes). 

If  the  rate  of  discharge  is  less  than  the  normal  rate,  the 
voltage  should  not  be  allowed  to  go  so  low. 

Limiting  voltage  ..........  cells  ..........  volts. 

Limiting  voltage  ..........  cells  ..........  volts. 

(c)  Never  allow  the  battery  to  stand  in  a  compktely 
discharged  condition. 


ELECTRIC   INTERLOCKING   HANDBOOK  153 


5.  READINGS 

(a)  Read  and  record  the  specific  gravity  of  the  pilot  cell 
and  battery  voltage  just  before  starting  and  ending  every 
charge,  together  with  the  temperature  of  the  electrolyte. 

(6)  To  properly  compare  the  specific  gravity  readings, 
they  should  be  corrected  to  standard  temperature  (seventy 
(70)  degrees  Fahr.)  by  adding  one  (1)  point  for  every 
three  (3)  degrees  above,  and  subtracting  one  (1)  point  for 
every  three  (3)  degrees  below  standard  temperature. 

(c)  Once  every  two  (2)  weeks,  after  the  end  of  the 
charge  preceding  the  overcharge,  read  and  record  the 
gravity  of  each  cell  in  the  battery. 

6.  INSPECTION 

(a)  Carefully  inspect  each  cell  on  the  day  before  the 
overcharge,  using  a  lamp  on  an  extension  cord  for  the 
purpose.  Examine  between  the  plates  and  hanging  lugs 
to  make  sure  that  they  are  not  touching,  and  also  make  a 
careful  note  of  any  peculiarity  in  color,  etc.,  of  the  plates. 

(6)  Use  a  strip  of  wood  or  hard  rubber  in  removing 
short  circuits.  NEVER  USE  METAL. 

(c)  Toward  end  of  the  charge  preceding  the  overcharge, 
note  any  irregularity  of  gassing;  cells  gassing  slowly 
should  be  investigated. 

7.  INDICATIONS  OF  TROUBLE 

(a)  FALLING  OFF  IN  SPECIFIC  GRAVITY  OR  VOLTAGE 
relative  to  the  rest  of  the  cells. 

(6)  LACK  OF  OR  SLOWER  GASSING  on  overcharge,  as 
compared  with  adjoining  cells. 

(c)  COLOR  OF  PLATES  markedly  lighter  or  darker  than 
in  adjoining  cells,  except  that  sides  of  plates  facing  glass, 
may  vary  considerably. 

(d)  In  case  of  any  of  the  above  symptoms  being  found, 
examine  carefully  for  cause,  and  REMOVE  AT  ONCE. 

(e)  Report  trouble  of  any  description  at  once  to 


8.  BROKEN  JARS 

If  a  jar  should  break,  and  there  is  no  other  to  take  its 
place,  so  that  the  plates  will  have  to  remain  out  of  serv- 
ice for  some  time,  keep  the  negatives  covered  with  water 
and  allow  the  positives  to  dry.  Connect  into  circuit  again 
lust  before  a  charge,  so  that  the  plates  will  receive  the 
benefit  of  the  charge. 

9.  OTHER  IMPORTANT  POINTS 

(a)  Plates  must  always  be  kept  COVERED  WITH  ELECTRO- 
LYTE. 

(V)  Use  only  CHEMICALLY  PURE  WATER,  preferably  dis- 
tilled, to  replace  evaporation. 


154  GENERAL  RAILWAY  SIGNAL  COMPANY 


(c)  NEVER  ADD  ELECTROLYTE  EXCEPT  under  the  condi- 
tions explained  above. 

(d)  Never  allow  the  SEDIMENT  to  get  to  the  bottom  of 
the   plates;     remove   sediment   when   the   clearance   has 
reached  one-half  (MO  inch. 

(e)  VENTILATE  the  room  freely,  especially  when  charging. 
(/)  Never  bring  an  EXPOSED  FLAME  near  the  battery 

when  charging. 

(0)  NEVER  ALLOW  METALS  OR  IMPURITIES  of  any  kind  to 
get  into  the  cells;    if  this  happens,  remove  and  wash  the 
plates  and  renew  the  electrolyte. 

(h)    Fill  out  the  report  sheets  regularly. 

(1)  READ  THE  GENERAL  INSTRUCTIONS  CAREFULLY. 


REQUIRED  CAPACITY   OF  STORAGE   BATTERIES 

USED  WITH  G.  R.  S.  ELECTRIC 

INTERLOCKING 

A  storage  battery  of  fifty-five  to  fifty-seven  cells,  having 
an  approximate  potential  of  110  volts,  is  used  in  connection 
with  G.  R.  S.  electric  interlocking  installations.  The  required 
ampere  hour  capacity  is  dependent  on  a  number  of  variables, 
viz :  the  number  of  days  between  charges,  frequency  of  lever 
movements,  amount  of  current  required  for  lighting,  for  cut- 
outs, indicators,  annunciators,  etc.,  and  the  number  of  days 
of  reserve  power  desired. 

A  separate  low  voltage  battery  is  generally  installed  when 
there  are  a  number  of  locks,  indicators,  relays,  etc.,  required 
at  the  plant,  as  this  type  of  device  is  more  efficient  and  can 
have  a  more  rugged  magnet  winding  when  designed  for  opera- 
tion on  a  potential  of  10  or  20  volts;  furthermore,  there  are 
certain  safety  features  which  can  be  secured  in  connection 
with  this  low  voltage  control.  The  capacity  of  such  a  low 
voltage  battery  is  determined  in  the  same  manner  as  the  high 
voltage  battery,  as  given  hereafter. 

The  following  instructions  will  enable  the  determination, 
with  reasonable  accuracy,  of  the  ampere  hour  capacity  of  the 
battery  required  for  use  with  a  G.  R.  S.  electric  interlocking 
plant. 

AMPERE  HOUR  CAPACITY  REQUIRED  FOR  OPERATION  OF 
FUNCTIONS     (See  also  table  on  page  158.) 

The  ampere  hour  capacity  required  for  the  operation  of 
functions  is  obtained  by  multiplying  the  number  of  lever 
movements  per  day  by  the  number  of  days  between  charges 
and  by  a  "Function  Constant."  This  constant,  to  be  obtained 
by  reference  to  table  on  page  155,  is  influenced  mainly  by  two 
things:  the  average  length  of  time  that  signals  are  held  in 


ELECTRIC   INTERLOCKING   HANDBOOK 


155 


the  proceed  position  and  the  ratio  of  the  number  of  signal 
movements  to  switch  movements.  In  the  absence  of  definite 
information  on  these  points  it  is  suggested  that  the  constant 
.006  be  used  as  representing  a  fair  average  condition.  This 
constant  is  shown  underlined  in  the  table. 

By  reference  to  the  table  of  Function  Constants  it  can  be 
easily  seen  that  it  is  advisable  to  keep  down  the  length  of 
time  signals  are  held  in  the  proceed  position,  a  glance  indicat- 
ing that  the  battery  capacity  will  run  up  very  rapidly  as  the 
time  of  holding  signals  at  proceed  increases.  In  this  connec- 
tion it  may  be  stated  that  there  have  been  cases  where  a  much 
smaller  size  battery  has  been  permitted  due  to  the  saving  in 


TABLE   OF   FUNCTION   CONSTANTS 


Average  Length  of  Time  Signals  are 
Held  in  Proceed  Position 
Minutes 

Ratio  of  Signal  to  Switch  Movements 

1-2 

1-3 

1-4 

1-5 

2 

.006 

.005 

.005 

.005 

3 

.007 

.006 

.006 

.006 

5 

.010 

.008 

.007 

.007 

10 

.016 

.013 

.011 

.010 

15 

.022 

.017 

.015 

.013 

30 

.041 

.032 

.026 

.023 

hold  clear  current,  this  being  effected  by  the  installation  of 
annunciators,  which  by  suitably  indicating  the  approach  of 
a  train  reduces  the  length  of  time  of  holding  the  signals  at 
proceed.  Furthermore,  it  is  interesting  to  note  that  the  saving 
effected  by  the  installation  of  this  smaller  battery  may  more 
than  balance  the  cost  of  such  annunciator  installation. 


AMPERE  HOURS  REQUIRED  FOR  OPERATING 
SWITCHBOARD  CUT-OUTS 

In  every  G.  R.  S.  electric  interlocking  plant  one  or  more 
circuit  breaker  cut-outs  are  required  for  cross  protection  pur- 
poses. The  capacity  required  for  cut-outs  is  obtained  by 
multiplying  the  number  of  cut-outs  by  nine-tenths  and  by 
the  number  of  days  between  charges.  A  discussion  as  to  the 
number  of  cut-outs  to  be  employed  to  suitably  sectionalize  a 
plant  is  given  on  page  93. 

AMPERE  HOURS  REQUIRED  FOR  ELECTRIC  LIGHTING 
(See  page  127.) 

When  the  signals  at  an  interlocking  plant  are  to  be  lighted 
by  electricity,  the  interlocking  battery  is  generally  held  as  a 
reserve  against  the  failure  of  the  normal  source  of  power. 
The  number  of  days  which  the  battery  may  be  called  upon  to 


156 


GENERAL  RAILWAY  SIGNAL  COMPANY 


furnish  current  in  such  an  event  depends  upon  the  probable 
length  of  time  required  to  repair  any  derangement  of  the 
apparatus  normally  furnishing  power  to  the  lighting  system. 
The  ampere  hour  capacity  which  must  be  provided  for  the 
lighting  is,  therefore,  determined  by  multiplying  the  ampere 
hours  per  signal  per  day  by  the  number  of  signals  to  be  lighted 
and  the  number  of  days'  operation  which  may  be  required 
between  charging  periods. 

TABLE  OF  AMPERE  HOURS  PER  DAY  PER  SIGNAL.     110  VOLT 

CARBON  FILAMENT  BULBS  —  TWO  BULBS  PER  SIGNAL, 

CONNECTED   IN   MULTIPLE 


Candle  Power 
per  Bulb 

AVERAGE  NUMBER  OF  HOURS  LIGHTS  ARE  BURNED 
PER  DAY 

12 

13                              U 

Ampere  Hours 

Ampere  Hours 

Ampere  Hours 

2 
4 

2.18 
4.36 

2.36 
4.72 

2.55 
5.09 

NOTE. — Values  approximate. 


AMPERE  HOURS  REQUIRED  FOR  MISCELLANEOUS 
PURPOSES 

When  auxiliary  devices,  such  as  indicators,  locks,  etc.,  are 
operated  from  the  interlocking  battery,  the  current  taken  for 
this  purpose  must  be  included  in  figuring  the  capacity  of  the 
battery.  The  current  required  by  these  devices  can  be  secured 
by  reference  to  tables  on  pages  265  to  269.  The  capacity  of 
battery  required  for  this  purpose  is  obtained  by  multiplying  the 
current  taken  by  said  auxiliary  devices  by  the  average  number 
of  hours  such  apparatus  is  energized  per  day,  and  by  the  num- 
ber of  days  between  charges. 

RESERVE  AMPERE  HOURS 

Under  normal  operating  conditions  the  battery  should  not 
be  fully  discharged  on  account  of  the  fact  that  charging  cur- 
rent may  not  be  always  instantly  available  when  wanted,  in 
which  case  the  time  would  surely  come  when  the  plant  would 
be  without  means  of  operation.  It  is,  therefore,  necessary  to 
have  the  battery  of  such  size  that  at  the  usual  time  of  charging 
there  will  be  a  certain  number  of  ampere  hours  capacity  left 
in  the  battery  as  a  reserve. 

The  R.  S.  A.  recommends  that  under  normal  conditions  the 
battery  never  be  discharged  beyond  two-thirds  of  its  total 
capacity;  stated  in  other  words,  this  means  that  50  per 
cent,  must  be  added  to  the  capacity  computed  when  installing 
the  battery  in  accordance  with  R.  S.  A.  specifications.  If  the 


ELECTRIC   INTERLOCKING   HANDBOOK  157 


battery  is  to  be  charged  at  intervals  of  a  week  this  will  give 
a  reserve  of  three  and  one-half  days,  and  if  at  intervals  of 
two  weeks  the  reserve  will  be  for  seven  days.  When  a  com- 
mercial source  of  power  is  available,  this  in  all  probability 
will  give  more  reserve  than  would  be  necessary.  On  the 
other  hand,  if  the  charging  source  is  not  so  reliable,  the  capacity 
of  the  battery  may  have  to  be  increased.  For  instance,  the 
charging  of  the  batteries  at  an  isolated  plant  may  be  dependent 
upon  a  gasoline  engine,  the  failure  of  which  might  take  several 
days  for  repairs  due  to  time  spent  in  securing  repair  parts,  etc. 
In  such  a  case  when  the  charging  is  done  at  intervals  of  a 
week,  it  would,  perhaps,  be  necessary  to  have  a  reserve  suf- 
ficient for  a  full  week's  operation,  this  requiring  that  the 
computed  capacity  of  the  battery  be  increased  by  100  per 
cent. 

Based  on  the  above,  it  is  recommended  as  good  practice  that 
the  battery  provide  for  a  minimum  reserve  of  50  per  cent, 
and  that,  if  local  conditions  require  it,  an  additional  amount 
of  reserve  be  added  as  outlined  above. 

METHOD  OF  TABULATION 

When  determining  the  capacity  of  a  battery  the  different 
items  may  be  tabulated  as  shown  below;  in  which — 

L  stands  for  'lever  movements  per  day." 

C  stands  for  'function  constant." 

D  stands  for  'days  operated  between  charges." 

N  stands  for  'number  of  units  operated." 

AH  stands  for  'ampere  hours  per  day  per  signal." 

A  stands  for  'amperes." 

H  stands  for  'hours  energized  per  day." 

Functions LxCxD          = ampere  hours 

Cut-Outs °/io  x  H  x  D       = ampere  hours 

Lighting  Signals AH  x  N  x  D      = ampere  hours 

Auxiliary  Apparatus  ....AxHxNxD= ampere  hours 

Total  of  above = ampere  hours 

Reserve  to  be  added = ampere  hours 

Total  capacity  of  Battery = ampere  hours 

WHEN  THE  NUMBER  OF  LEVER  MOVEMENTS 
is  NOT  KNOWN 

When  it  is  not  possible  to  ascertain  the  number  of  lever 
movements  to  be  made  in  a  given  plant,  the  ampere  hour 
capacity  of  battery  required  for  the  operation  of  functions 
and  for  cut-outs  can  be  secured  from  the  following  table; 
these  figures  include  sufficient  reserve  to  care  for  ordinary 
conditions. 


158 


GENERAL  RAILWAY   SIGNAL  COMPANY 


TABLE   GIVING    BATTERY   CAPACITY    FOR   OPERATION 
FUNCTIONS   AND   CUT-OUTS 


OF 


Size  of  Machine 

Size  of  Battery 

8  to    16  levers 
16  to    32  levers 
32  to    48  levers 
48  to    88  levers 
88  to  128  levers 
128  to  168  levers 

40  ampere  hour  battery 
60  ampere  hour  battery 
80  ampere  hour  battery 
120  ampere  hour  battery 
160  ampere  hour  battery 
200  ampere  hour  battery 

The  table  is  based  on  past  experience  and  is  considered  rea- 
sonably correct  for  moderate  size  machines,  the  battery  sizes, 
if  anything,  being  somewhat  high.  The  table  is  not  extended 
for  machines  larger  than  168  levers,  as  with  such  plants  it  is 
believed  that  special  study  of  lever  movements  should  be 
made  in  the  determination  of  the  battery  size. 

If  the  signals  are  to  be  lighted  and  auxiliary  apparatus 
operated  from  the  interlocking  battery,  an  additional  number 
of  ampere  hours  must  be  added  to  the  figures  in  the  table, 
the  calculation  being  made  in  accordance  with  the  preceding 
paragraphs  dealing  with  the  capacity  required  for  electric 
lighting  and  for  miscellaneous  purposes. 


FIG.  107. 


FRONT  ELEVATION  SECTION  A  B. 

LEAD  TYPE  STORAGE  BATTERY  AND  BATTERY  CUPBOARD 


ELECTRIC   INTERLOCKING  HANDBOOK 


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GENERAL  RAILWAY   SIGNAL  COMPANY 


G.  R.  S.  BATTERY  CHARGING   SWITCH 

The  battery  charging  switch  illustrated  by  Fig.  108  provides 
a  simple  and  efficient  means  for  connecting  storage  batteries 
in  series  with  charging  and  discharge  lines,  permitting  the 
batteries  to  be  switched  off  or  on  to  the  line  without  opening 
the  charging  circuit. 

During  the  manipulation  of  the  switch,  short  circuiting  of 
the  battery  is  avoided  by  automatically  inserting  a  resistance 
during  the  interval  that  the  battery  would  otherwise  be  on 


FIG.  108.     BATTERY  CHARGING  SWITCH 

short  circuit,  which  resistance  is  again  cut  out  as  soon  as  that 
point  is  passed. 

Manipulation  of  the  switch  is  simple,  the  four  different 
positions  of  the  switch  controlling  the  battery  as  follows: 

1  —  Battery  A  discharging,  Battery  B  charging. 

2  —  Battery  A  discharging,  Battery  B  open. 

3  —  Battery  B  discharging,  Battery  A  open. 

4  —  Battery  B  discharging,  Battery  A  charging. 

The  charging  switch  is  compact  and  substantial  in  design 
and  so  arranged  to  permit  of  easy  inspection.  The  commu- 
tator possesses  a  high  degree  of  insulation.  The  contact 
plates  and  fingers  are  large,  being  designed  to  take  care  of  the 
neavy  currents  necessary  in  this  kind  of  work  without  heating. 


ELECTRIC   INTERLOCKING   HANDBOOK 


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DIRECT  CURRENT  GENERATORS 
GENERAL  DESCRIPTION  OF  CHARGING  APPARATUS 

DIRECT  current  generators  of  the  shunt  wound  type  are 
ordinarily  used  for  storage  battery  charging.  The 
capacities  of  the  generators  used  in  connection  with  the 
G.  R.  S.  electric  interlocking  system  run  from  1  to  8  K.  W., 
as  shown  in  the  table  on  page  159,  the  current  being  delivered 
at  a  potential  ranging  from  110  to  160  volts. 

Where  commercial  power  is  available,  it  is  preferable  to 
use  a  direct  connected  motor  for  operating  the  charging  gen- 
erator. Where  such  power  is  not  available,  a  gasoline  engine 
is  generally  employed  to  drfVe  the  generator,  either  by  means 
of  belting  or  by  being  directly  connected  to  the  generator. 

The  charging  is  generally  controlled  through  the  medium  of 
a  power  switchboard  equipped  with  a  no-load,  reverse-current 
circuit  breaker,  which  opens  the  charging  circuit  if  the  gener- 
ator voltage  drops  below  that  of  the  batteries,  thus  preventing 
the  generator  from  running  as  a  motor  on  current  delivered 
by  the  batteries. 

A  simplified  charging  circuit  is  shown  by  Fig.  110.  In  this 
circuit  the  generator  is  assumed  connected  for  right-hand 
rotation;  to  secure  left-hand  rotation  the  field  connection 
should  be  reversed. 

SETTING  UP  THE  MACHINE 

The  generator  should  be  located  in  a  room  which  is  as  dry 
and  clean  as  possible:  a  room  which  is  hot  and  dusty  should 
be  avoided,  particularly  if  the  dirt  is  of  a  gritty  character,  as 
it  is  apt  to  injure  the  commutator  and  bearings  of  the  machine. 

The  machine  should  be  in  plain  sight  and  have  sufficient 
room  on  all  sides  for  easy  access,  care  being  taken  that  there 
is  sufficient  room  to  permit  taking  out  the  armature. 

If  the  flooring  of  the  power  house  is  firm,  the  generator  or 
motor  generator  set  may  be  mounted  on  a  wood  block  three 
or  four  inches  thick,  screwed  to  the  flooring;  if  the  floor  con- 
struction will  not  permit  this,  a  concrete  foundation  should 
be  installed. 

WHEN  STARTING  GENERATOR  FOR  THE  FIRST  TIME 

Before  starting  the  machine  for  the  first  time,  make  sure 
that  the  main  switch  and  circuit  breaker  are  open  (Fig.  110). 
Raise  the  brushes  from  contact  with  the  commutator  and 
examine  them  to  see  if  they  are  in  proper  condition.  Fill 
the  bearings  with  oil.  Make  sure  that  the  armature  and  field 
coils  of  the  generator  have  not  become  wet  during  shipment 
or  while  being  stored ;  if  any  sign  of  dampness  is  noted  they 
should  be  dried  out,  following  the  instructions  on  page  165. 

Run  the  generator  light  for  a  time,  noting  whether  the  oil 
rings  are  working  properly,  and  if  the  generator  is  belt  driven, 


ELECTRIC  INTERLOCKING   HANDBOOK  163 

note  whether  the  machine  is  so  lined  up  that  the  belt  runs 
central  on  the  pulleys  and  the  armature  plays  freely  back  and 
forth  between  its  bearings.  At  no-load  the  speed  of  the  gener- 
tor  should  be  slightly  high,  so  that  at  full-load  it  will  come 
down  to  approximately  that  indicated  on  the  name  plate. 

After  making  sure  that  the  commutator  brushes  are  still 
raised,  cut  the  rheostat  fully  "in"  and  then  close  the  main 
switch  and  the  circuit  breaker  (Fig.  110).  Cut  the  rheostat 
"out"  gradually  and  then  "in"  again,  after  which  the  main 
switch  should  be  again  opened.  This  procedure  causes  cur- 
rent to  flow  through  the  generator  fields  and  insures  the 
field  coils  having  a  proper  residual  magnetism.  Replace  the 
brushes  on  the  commutator  and  shift  the  brush  holder,  if 
necessary,  to  bring  the  brushes  to  the  "neutral"  position. 

POWER  SHITCH  BOARD 
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STORAGE.     -= 
BATTERY  •**-= 

1 

FIG.  110.     SIMPLIFIED  CHARGING  CIRCUIT 

After  the  machine  is  running  and  has  built  up,  the  brushes 
should  be  rocked  backward  and  forward  until  the  point 
of  minimum  sparking  is  found.  When  the  machine  is  run- 
ning under  load  this  should  be  again  checked  and  the  position 
of  the  brushes  shifted  again  if  necessary;  lock  and  leave 
brushes  in  this  position. 

To  START  THE  CHARGE 

See  that  the  main  switch  and  circuit  breaker  are  open,  and 
that  the  rheostat  resistance  is  all  cut  "in." 

Get  the  generator  up  to  speed  and  make  sure  that  the 
brushes  are  in  proper  position  and  that  the  oiling  rings  are 
working  properly. 

See  that  the  belt  has  the  proper  tension ;  that  is,  it  should 
be  as  loose  as  possible  and  yet  not  slip  or  tend  to  run  off  the 
pulley  with  load  on. 

Cut  the  rheostat  resistance  "out"  until  the  voltage  is  a 
little  higher  than  that  of  the  battery,  being  sure  that  the 
voltmeter  needle  deflects  in  the  same  direction  for  both 
generator  and  battery  (see  switch  No.  2,  Fig.  118).  This 


164  GENERAL  RAILWAY  SIGNAL  COMPANY 


latter  insures  that  the  positive  terminal  of  the  generator  will 
be  connected  to  the  positive  pole  of  the  battery. 

Close  the  main  switch  and  circuit  breaker  and  adjust  the 
rheostat  until  the  proper  amount  of  current  is  flowing  into 
the  battery,  also  adjust  the  brushes  if  necessary  for  minimum 
sparking.  It  will  be  necessary  to  change  the  adjustment  of 
the  rheostat  occasionally  as  the  battery  charging  increases,  in 
order  to  maintain  the  current  at  the  proper  amount. 

To  SHUT  DOWN 

To  shut  down,  lower  the  voltage  by  cutting  "in  "  the  rheostat 
until  the  circuit  breaker  on  the  switchboard  opens  of  itself 
and  then  stop  the  engine.  If  no  circuit  breaker  is  provided, 
wait  until  the  current  is  practically  at  zero  before  opening  the 
main  switch  on  the  battery.  After  the  machine  has  stopped, 
relieve  the  tension  on  the  belt  so  as  to  prevent  it  from  stretch- 
ing during  such  time  as  the  machine  is  standing  idle. 

GENERAL  INSTRUCTIONS 

It  is  hardly  possible  to  give  detailed  and  complete  instruc- 
tions in  these  pages  for  locating  all  the  troubles  which  may 
arise  in  the  use  of  such  apparatus.  The  type  of  machine 
used  for  charging  storage  batteries  is  so  simple,  however,  that 
by  adhering  to  the  following  general  instructions,  it  is  believed 
that  satisfactory  operation  of  the  machine  will  be  obtained. 

The  generator  should  be  kept  perfectly  clean  and  dry  and 
should  not  be  unnecessarily  exposed  to  dust.  This  can  best 
be  accomplished  by  throwing  a  waterproof  covering  over  the 
machine  when  not  in  use. 

Do  not  overload  the  machine.  To  load  the  machine  beyond 
the  capacity  indicated  on  its  name-plate  is  never  conducive 
to  best  operation,  this  being  the  frequent  cause  of  over- 
heating in  the  machine,  sparking  at  the  commutator,  or  other 
troubles. 

Overheating  the  generator  may  be  readily  detected  by 
applying  the  hand  to  the  various  parts  of  the  machine;  in 
general  a  temperature  that  cannot  be  borne  by  the  hand  is  to 
be  considered  excessive.  An  odor  of  burning  varnish  is  indi- 
cative of  serious  overheating,  and  a  machine  which  shows  this 
symptom  should  have  the  load  removed  at  once;  rotation  of 
the  armature  may  be  continued  with  the  fields  de-energized 
for  the  purpose  of  cooling  the  machine. 

The  <  bearings  should  be  kept  thoroughly  lubricated  with 
the  bqst  grade  of  lubricating  oil.  While  the  machine  is  run- 
ning, care  should  be  taken  from  time  to  time  to  see  that  the 
oiling  rings  are  working  correctly. 

Particular  attention  should  be  given  to  the  commutator 
and  brushes  to  see  that  the  former  keeps  perfectly  smooth 
and  that  the  latter  are  in  perfect  adjustment.  The  commuta- 
tor should  assume  a  dark  brown,  glossy  appearance,  if  proper 
brushes  are  used  and  are  kept  from  sparking,  and  if -the 


ELECTRIC  INTERLOCKING   HANDBOOK  165 


capacity  of  the  machine  as  indicated  on  the  name  plate  is  not 
exceeded.  The  condition  of  the  commutator  and  brushes  may 
be  regarded  as  the  best  barometer  of  the  condition  of  the 
generator. 

The  free  use  of  lubricants  on  the  commutator  is  not  recom- 
mended. In  cleaning  the  commutator  a  tightly  woven  cloth 
(free  from  lint)  or  chamois  skin,  should  be  used  and  the 
commutator  then  wiped  with  a  rag  which  has  a  little  vaseline 
on  it. 

To  fit  the  brushes  to  the  commutator  draw  No.  00  sand- 
paper under  them,  smooth  side  to  the  commutator,  as  shown 
in  Fig.  Ill,  the  brushes  to  bear  on  the  sandpaper  only  when 


HANDLE 


COMMUTATOR  ' 

Fia.  111.     METHOD  OF  FITTING  BRUSHES  TO  COMMUTATOR 

it  is  being  drawn  in  the  direction  in  which  the  surface  of  the 
commutator  will  run  when  the  machine  is  in  operation.  After 
the  brush  is  shaped  to  the  commutator  finish  up  with  No.  0 
sandpaper  and  then  carefully  clean  the  commutator  and 
brushes  of  all  particles  of  dust  or  grit. 

The  brushes  shipped  with  the  machine  are  ordinarily  best 
adapted  to  the  work  and  other  brushes  are  liable  to  cause 
trouble.  A  little  oil  may  be  applied  to  the  brushes  should 
they  become  dry  and  noisy. 

If  the  armature  or  field  coils  of  the  generator  should  become 
wet,  they  should  be  thoroughly  dried  out  before  running  the 
machine  under  load  as  the  moisture  is  liable  to  damage  the 
windings.  The  coils  of  the  machine  may  be  dried  out  by 
baking  in  an  oven  at  a  temperature  of  240  degrees  Fahr. 
for  several  hours,  or  if  an  oven  is  not  available  they  may 
be  dried  out  by  placing  near  the  fire.  Another  method  is 
to  run  the  generator  for  several  hours  without  exciting  its 
field. 


166  GENERAL  RAILWAY  SIGNAL  COMPANY 


GENERATOR  FAILS  TO  BUILD  UP 

One  of  the  common  troubles  which  occurs  in  the  operating 
of  generators  is  the  failure  of  the  machine  to  build  up.  This 
failure  may  be  generally  attributed  to  one  of  the  following 
causes: 

1.  Open  circuit  due  to  a  broken  wire,  faulty  connec- 
tions, brushes  up,  fuse  blown,  open  switch,  etc. 

2.  Reversed  connections  in  field  circuit  or  reversed 
direction  of  rotation. 

3.  Excessive  resistance   due  to  poor  brush  contact. 
Brush  contacts  often  have  an  excessively  high  resistance 
when  generator  is  first  started,  and  a  momentary  pressure 
of  the  fingers  on  the  brush  or  brushes  may  enable  the 
machine  to  build  up. 

4.  Weak,  destroyed  or  reversed  residual  magnetism. 
To  restore  residual  magnetism  send  current  from  battery 
through  the  fields  in  the  proper  direction. 

5.  Brushes  not  in  their  proper  position. 

6.  Short  circuit  in  the  machine  or  in  the  external 
circuit. 


R.  S.  A.  SPECIFICATIONS   FOR   ELECTRIC 

GENERATOR  (1910) 
1.    MATERIAL 

(a)  The  generator  shall  be  shunt  wound,  self-excited,  shall 
have  self-oiling  bearings,  carbon   brushes,  rheostat,  and 
when  belt  connected,  a  belt  tightener,  sub-base,  and  pulley. 

(b)  The  normal  or  rated  speed  shall  not  exceed  fifteen 
hundred  (1500)  r.  p.  m.  except  when  direct  connected  to  an 
a.  c.  motor  or  steam  turbine. 

(c)  The    generator    shall    have    a    continuous    current 

capacity  equal  to  the  eight  (8)  hour  rate  ( 

ampere)  of  the  battery,  at  a  voltage  equal  to  the  maximum 

voltage  ( volts)  of  the  battery  on  charge, 

without   a   rise   in   temperature   in   any   part   exceeding 
seventy-two  (72)  degrees  Fahr.  (40°  C.)  above  the  tem- 
perature of  the  surrounding  atmosphere. 

(d)  It  shall  be  so  wound  that  its  voltage  at  the  con- 
tinuous current  rating  given  above,  may  be  varied  by 
means  of  a  field  rheostat  between  the  minimum  and  the 
maximum  charging  voltage  of  the  battery. 

(e)  The  generator  shall  be  capable  of  supplying  for  four 
(4)  hours  a  current  output  twenty-five  (25)  per  cent,  in 
excess  of  the  continuous  current  capacity  referred  to  in 
above  without  a  rise  in  temperature  in  any  part  exceeding 
ninety  (90)  degrees  Fahr.  (50°  C.)  above  the  temperature 
of  the  surrounding  atmosphere. 

(/)  It  is  understood  that  the  temperature  of  the  sur- 
rounding atmosphere  is  to  be  based  on  seventy-seven  (77) 


ELECTRIC   INTERLOCKING   HANDBOOK  167 


degrees  Fahr.  (26°  C.),  but  should  the  temperature  vary 
from  this,  corrections  shall  be  made  in  accordance  with 
the  recommendations  of  the  American  Institute  of  Elec- 
trical Engineers. 

(gr)  The  current  output  of  the  minimum  allowable  gen- 
erator shall  be  that  required  for  the  operation  of  two  (2) 
switches  simultaneously. 

(ft)  With  the  brushes  in  a  fixed  position,  the  generator 
shall  be  practically  sparkless  under  all  operating  condi- 
tions, as  outlined  above. 

(i)  These  generator  specifications  describe  a  machine 
which,  in  normal  power  interlocking  service,  will  have  an 
ample  overload  capacity  to  meet  general  requirements. 


168 


GENERAL  RAILWAY  SIGNAL  COMPANY 


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GASOLINE  ENGINES 
GENERAL  DESCRIPTION 

GASOLINE   engines,  used  in  the  charging  of  moderate 
sized   storage   batteries,    are    generally   of    the    single 
cylinder  four  cycle  type,    water  cooled  and  equipped 
with  the  "Make  and  Break"  electric  ignition.     The  vertical 
type  engine  is  lubricated  by  the  crank  dipping  into  an  oil 
bath  in  the  base  of  the  crank  case;    oil  and  grease  cups 
are    further    provided    for    lubricating   parts    not    so    cared 
for. 

The  operation  of  the  engine  is  maintained  at  a  constant  speed 
by  either  regulating  the  mixture  of  gasoline  vapor  or  by 
varying  the  number  of  power  impulses  as  soon  as  a  certain 


A-  Circulating  Tank       D  -  Vent 

B-  Return  Pipe  E-  Drain  Pipe 

C-  Supply  Pipe  F-  Valve 

G-  Exhaust  Pipe  -  Engine  to  exhaust  Rot 

FIG.  114.     WATER  CONNECTIONS  FOR 

GASOLINE  ENGINE  USING 

COOLING  TANK 


FIG.  115.    WATER  CONNECTIONS 

FOR    GASOLINE    ENGINE 

COOLED  BY  RUNNING 

WATER 


speed  is  exceeded ;  the  engines  so  controlled  are  known  as  the 
"Throttling  Governor"  or  the  "Hit  and  Miss"  types,  respect- 
ively. 

In  a  common  type  of  engine  used  for  this  work,  a  pump 
supplies  gasoline  to  a  reservoir,  an  overflow  pipe  being  con- 
nected with  the  reservoir  to  maintain  the  gasoline  at  a  uniform 
height.  At  the  proper  time  in  the  cycle  of  operation,  the 
engine  piston  sucks  air  through  the  air  inlet  passage  and  at 
such  a  velocity  that  gasoline  is  picked  up  from  the  reservoir 
and  drawn  through  an  adjustable  nozzle  into  the  cylinder 
head,  the  gasoline  mixing  with  the  air  to  form  the  required 
explosive  vapor. 


ELECTRIC   INTERLOCKING   HANDBOOK 


171 


LOCATION  OF  ENGINE 

In  locating  the  engine,  at  least  two  feet  should  be  left  on 
all  sides  of  engine  for  convenience  in  starting  and  for  having 
sufficient  room  to  make  necessary  adjustments  and  repairs. 

The  gravity  system  of  circulation  is  generally  used  for  the 
cooling  water.  With  this  system,  the  tank  for  the  cooling 
water  is  generally  placed  on  the  floor,  as  shown  in  Fig.  114 ;  best 
results  are  secured,  however,  by  having  the  tank  elevated 
enough  to  bring  the  bottom  above  the  lower  water  opening  on 
the  engine  cylinder.  Connections  should  be  as  shown,  large 
enough  piping  being  used  to  permit  free  circulation  of  the 
water.  Valves  F-F  must  be  inserted  in  the  pipe  line  to  permit 
drawing  off  the  water  from  engine  in  freezing  weather  without 
emptying  the  tank. 

The  gasoline  tank  should  be  located  outside  of  the  building, 


FIG.  116.     GASOLINE  TANK  LOCATION 


and  with  engines  equipped  with  a  gasoline  pump,  the  tank 
should  be  placed  at  a  lower  level  than  the  engine,  so  that  when 
the  engine  is  idle  the  gasoline  will  drain  back  into  the  tank. 
In  making  the  connections  between  the  gasoline  tank  and 
engine,  care  must  be  taken  to  wash  out  all  piping  and  joints 
with  gasoline  to  remove  any  loose  matter  or  scale  from  the 
interior  of  such  connections. 

To  START  ENGINE 

See  that  engine  is  properly  oiled  and  that  water  and  gasoline 
valves  are  turned  on.  Pump  gasoline  into  reservoir.  Fill 
priming  cock  on  head  of  cylinder;  this  may  not  be  necessary 
in  warm  weather.  Make  sure  that  spark  lever  is  in  "retard" 
or  "late"  position,  then  close  switch  to  ignition  circuit. 

Turn  engine  fly-wheel  in  normal  direction  of  rotation. 

After  ignition  occurs,  remove  starting  crank,  advance  spark 
lever  to  "early"  position  and  regulate  the  throttle  valve.  It 


172  GENERAL  RAILWAY  SIGNAL  COMPANY 


will  be  found  that  this  last  adjustment  varies  with  the  tem- 
perature, requiring  much  coarser  adjustment  with  cold  weather 
than  with  warm. 

Load  should  not  be  thrown  on  the  engine  until  after  it  is  in 
operation. 

To  STOP  ENGINE 

Close  throttle  valve  and  open  switch  on  battery.     If  it  is 
freezing  weather,  water  should  be  drawn  off  from  engine. 


GASOLINE   ENGINE   TROUBLES 

IGNITION  TROUBLES 
Engine  misses  or  fails  to  start 

(a)  Weakened  Batteries. 

(b)  Strong  Batteries,  but  with  following  defects: 

1.  Switch  in  "OFF"  position. 

2.  Insulation  on  wire  worn,  causing  short  circuit. 

3.  Circuit  open  by  broken  or  loose  connections. 

4.  "Make  and  Break"  mechanism  inoperative,  due 

to  broken  spring,  bearing  stuck,  etc. 

5.  "Make  and  Break"  mechanism  contacts  fouled. 

6.  "Make  and  Break"  adjustments  incorrect. 

7.  Broken  down  spark  coil. 

CARBURETION  DIFFICULTIES 
Engine  misses  or  fails  to  start 
(a)     Fuel  Supply  —  tank  and  pipe  line : 

1.  Throttle  valve  closed. 

2.  Tank  empty. 

3.  Tank  vent  stopped  up. 

4.  Gasoline  pump  inoperative. 

5.  Gasoline  pipe  plugged. 

6.  Water  in  gasoline. 
(6)     Mixture  too  rich : 

1.  Throttle  valve  adjustment  incorrect. 

2.  Air  passage  clogged. 

(c)  Mixture  too  weak : 

1.  Throttle  valve  adjustment  incorrect. 

2.  Spray  valve  partially  stopped  up. 

3.  Intake  pipe  leaky. 

Loss  OF  COMPRESSION 
Engine  misses,  looses  power,  or  fails  to  start 
(a)     Improper  valve  operation: 

1.  Valves  do  not  lift  at  proper  time ;  due  to  loosening 

or  stripping  of  gearing  on  cam  or  crank  shafts. 

2.  Valves  fail  to  seat  properly  or  too  slow;    due  to 

weak  spring. 


ELECTRIC   INTERLOCKING    HANDBOOK  173 


3.     Worn  cam  followers,  cams,  push  rods,  etc. 
(&)     Leaky  piston  rings. 

(c)  Priming  valve  open  or  leaky. 

(d)  Leak  in  cylinder  head  packing. 

(e)  Failure  of  lubricating  system  (engine  hot) : 

1.  Oil  valve  shut  off. 

2.  No  oil  in  oil  cups. 

3.  Oil  drained  out  of  crank  case  (vertical  engine). 
(/)     Failure  of  cooling  system  (engine  hot) : 

1.  Valve  in  water  piping  closed. 

2.  No  water  in  cooling  tank. 

3.  Water  below  normal  level   (gravity  system  of 

circulation). 

4.  Water  piping  plugged. 

5.  Pump  out  of  order  (forced  circulation). 

CANNOT  CRANK  ENGINE 

(a)  Engine  heated  due  to  failure  of  lubricating  or  cooling 

systems. 

(&)  Crank  or  connecting  rod  bearing  overheated  or  seized, 

(e)  Piston  overheated  or  seized. 

(d)  Timing  gears  broken  or  jammed. 

(e)  Connecting  rod  disconnected,  broken  or  bent. 
(/)  Crank  shaft  broken  or  bent. 

(0)     Water  in  pump  frozen  (force  system  of  water  circu- 
lation). 

MECHANICAL  DIFFICULTIES 
Engine  misses,  looses  power,  or  fails  to  start 

(a)     Externally  apparent : 

1.  Valve  spring  weakened  or  broken. 

2.  Valve  stem  bent,  broken,  or  gummed. 

3.  Valves  leaky  (carbon  on  seats). 

4.  Valve  stem  and  cam-follower  always  in  contact 

(no  clearance). 

5.  Muffler  or  exhaust  pipe  obstructed. 
(?>)     Internally  apparent : 

1.  Cylinders  or  valves  carbonized. 

2.  Piston  rings  gummed  or  broken. 

3.  Leaky  piston  rings,  slots  in  line. 

4.  Cam  head  worn,  shifted  or  broken.  * 

5.  Piston  head  or  cylinder  wall  cracked. 

6.  Piston  rings  and  cylinder  wall  scored. 

Loss  OF  POWER  WITHOUT  MISSING 

(a)  Ignition  system  adjustments  wrongly  set. 

(6)  Carbureter  adjustments  wrongly  set. 

(c)  Lubricating  system  operating  imperfectly. 

(d)  Cooling  system  operating  imperfectly. 

(e)  Poor  valve  operation. 

(/)     Batteries  weakened,  giving  poor  spark. 


174  GENERAL  RAILWAY  SIGNAL  COMPANY 

(gf)     Mechanical  difficulties,  such  as  worn  valve  connections, 

etc. 

(h)     Intake  pipe  leaky. 
(i)     Muffler  or  exhaust  obstructed. 
(/)      Engine  bearings  overheated. 


EDITOR'S    NOTE 

Above  articles  based  on  data  furnished  by  Fairbanks-Morse  & 
Company.  

R.  S.  A.  SPECIFICATIONS   FOR   GASOLINE   ENGINE 
WITH  FUEL  AND  WATER  TANKS  (1910) 

1.  ENGINE 

(a)  The  recommended  brake  horse  power  of  the  gasoline 
engine  shall  be  not  less  than  one  and  three-fourths  (1%) 
times  the  kilowatt  capacity  of  the  generator  at  the  maxi- 
mum voltage  and  the  eight  (8)  hour  charging  rate. 

(6)  The  engine  shall  run  without  injurious  vibration  and 
shall  operate  continuously  at  Manufacturer's  specified 
capacity  for  a  period  of  sixteen  (16)  hours  without  injurious 
heating  in  any  part. 

(c)  Regulation  in  speed  shall  be  within  three  (3)  per 
cent,  from  no  load  to  full  load  and  the  regulation  as  re- 
corded on  the  voltmeter  for  a  given  current  shall  not  vary 
more  than  two  (2)  per  cent,  between  impulses. 

(d)  Electrodes  on  the  engine  for  electric  ignition  shall  be 
tipped  with  platinum  or  an  equally  serviceable  material. 

(e)  Manufacturer's  standard  exhaust  muffler  shall  be 
provided. 

(/)  Engine  and  accessories  shall  be  acceptable  by  and 
installed  under  the  rules  of  the  National  Board  of  Fire 
Underwriters  and  the  attached  requirements  of  local 
authorities. 

(g)  Engines  of  twenty-five  (25)  horse  power  or  less  shall 
not  exceed  a  speed  of  four  hundred  (400)  r.  p.  m. 

2.  TANKS 

(a)  Gasoline  tank  of gallons  capacity  shall 

be  furnished.  Fuel  and  cooling  tanks  shall  be  made  of 
iron  or  steel  with  bra-zed  or  riveted  seams. 

(6)  Tanks  shall  be  galvanized  after  they  are  put  together. 

(c)  For  tanks  either  for  fuel  or  water,  selection  shall  be 
made,  when  practicable,  from  the  following  table: 

Gallons  Inches  in  Inches  in  Gauge  metal 

capacity          diameter  length  Head  Body 

66  18  68  14  16 

120  24  66  12  14 

500  36  120  10  12 

As  a  guide  in  ordering  tanks,  it  is  good  practice  to  con- 


ELECTRIC  INTERLOCKING  HANDBOOK  175 


sider  that  it  will  require  one-tenth  (Ho)  of  a  gallon  of  gaso- 
line per  horse  power  hour  for  gasoline  engines. 

(d)  For  cooling,  the  minimum  of  free  running  water 
should  be  not  less  than  ten  (10)  gallons  per  horse  power 
hour,  and  for  the  circulation  tank  system  not  less  than 
fifty  (50)  gallons  per  horse  power. 

(e)  Sufficient  piping  shall  be  furnished  to  locate  the 
gasoline  tank feet  from  the  engine. 

(/)  Unions  in  all  piping  shall  be  equipped  with  ground 
brass  seats. 

(g)  Unless  otherwise  specified,  an  iron  or  a  steel  cooling 
tank  of  sufficient  capacity  for  a  continuous  run  of  ten  (10) 
hours  on  one  (1)  filling,  with  connections  and  removable 
cover,  shall  be  furnished.  Connections  between  engine 
and  tank  shall  be  arranged  for  convenient  and  complete 
drainage  of  the  cooling  system,  for  independent  drainage 
of  the  engine  and  tank,  and  to  conduct  all  waste  water 
and  steam  to  the  outside  of  the  building. 

(h)  When  engine  is  installed  in  same  building  with 
storage  batteries  outside  air  intake  shall  be  provided. 


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ELECTRIC  INTERLOCKING  HANDBOOK 


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ELECTRIC   INTERLOCKING   HANDBOOK 


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ELECTRIC  INTERLOCKING  HANDBOOK 


181 


Motor 

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STARTING  PANEL  FOR 
D.  C.  MOTOR 


FIG.  128 


FIG.  129 
STANDARD  OPERATING  SWITCHBOARD 


Polar  Relay  Contacts 


To  test  for  ground,  throw  switch  No.  1  to  the  right  or  left.  If  the 
lamp  lights  when  pressed  to  the  right  it  shows  that  the  negative  wire  is 
grounded.  If  lamp  lights  when  pressed  to  the  left  it  shows  that  the 
positive  wire  is  grounded. 

Red  lamps  lighted  shows  that  the  circuit  breaker  is  open. 


182 


GENERAL  RAILWAY  SIGNAL  COMPANY 


12" 


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FIG.  130 

LIGHTING  PANEL  WITH  FIVE 

SINGLE  POLE,  SINGLE 

THROW  SWITCHES 


FIG.  131 

LIGHTING  PANEL  WITH  THREE 

DOUBLE  POLE,  SINGLE 

THROW  SWITCHES 


1 

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j 


FIG.  132 

LIGHTING  PANEL  WITH  TEN 

SINGLE  POLE,  SINGLE 

THROW  SWITCHES 


FIG.  133 

LIGHTING  PANEL  WITH  FIVE  SINGLE 

POLE,  SINGLE  THROW  SWITCHES 

AND  ONE  DOUBLE  POLE, 

DOUBLE  THROW 

SWITCH 


1 


H tz" — 

FIG.  134 

LIGHTING  PANEL  WITH  Two 

DOUBLE  POLE,  DOUBLE 

THROW  SWITCHES 


J 


FIG.  135 

LIGHTING  PANEL  WITH  FOUR 

SINGLE  POLE,  DOUBLE 

THROW  SWITCHES 


SECTION   VII 


INSTALLATION  AND  OPERATING  DATA  FOR 
ELECTRIC    INTERLOCKING   MACHINES 


COVERING  INSTRUCTIONS  FOR  INSTAL- 
LATION   AND    MAINTENANCE;  ALSO 
DATA    FOR    THE   APPLICATION   AND 
OPERATION   OF   LEVER   LOCKS 


INSTRUCTIONS    COVERING    THE    INSTALLA- 
TION   AND    MAINTENANCE    OF    THE 
MODEL    2    ELECTRIC    INTER- 
LOCKING   MACHINE 
SHIPMENT 

BEFORE  shipment  the  interlocking  machine  is  assembled 
complete  in  every  detail  and  subjected  to  a  rigid  electric 
and  mechanical  test.     It  is  then  partly  disassembled, 
the  levers,  lever  tappets  and  locking,  the  legs  and  lower  tiers 
of  locking  plates  (if  furnished)  being  boxed  separately  from 
the  body  or   the  machine.     This  latter  is  then  divided  into 
sections    of    approximately    forty   lever    spaces   and    boxed 
on  skids  for  shipment.     Before  boxing,  all  machined  parts 
are  wiped  dry  and  coated  with  vaseline  to  guard  against  the 
effects  of  rust  during .  transit. 

STORING 

Upon  the  receipt  of  the  machine  it  should  be  stored  in  a 
dry  place.  If  some  time  passes  before  the  machine  is  set  up 
and  there  is  any  chance  of  its  different  parts  rusting,  these 
parts  should  be  wiped  dry  and  recoated  with  vaseline. 

INSTALLATION 

The  first  step  in  the  assembly  of  the  machine  is  to  bolt  the 
sections  to  their  supporting  legs  and  the  various  sections  to 
each  other.  The  legs  are  numbered  and  the  machine  beds 
marked  to  correspond.  Extreme  care  should  be  taken  in 
shimming  up  under  the  legs  to  insure  accurate  alignment  of 
the  bed  and  an  even  distribution  of  the  weight  on  the  sup- 
porting legs.  Failure  to  do  this,  especially  in  a  large  machine, 
is  very  likely  to  result  in  binding  between  the  various  parts  of 
the  mechanical  locking. 

The  second  and  third  tiers  of  locking  plates,  if  used,  should 
be  assembled  on  the  machine,  care  being  taken  to  place  the 
templet  furnished  for  the  purpose  in  the  horizontal  and  vertical 
locking  slots  before  doweling  the  locking  plates  to  their  sup- 
port. Never  file  the  screw  holes  when  mounting  these  plates 
since  this  is  not  necessary  if  the  bed  has  its  correct  alignment. 
To  permit  of  the  plates  being  placed  in  the  same  location  as 
when  the  machine  was  assembled  in  the  factory,  the  second 
tier  of  plates  are  numbered  1,  2,  3,  etc.,  from  left  to  right,  and 
the  third  tier  1A,  2A,  3A,  etc.,  also  from  left  to  right. 

The  locking  should  then  be  assembled  in  the  locking  plates 
and  the  lever  tappets  placed  in  their  proper  positions.  Each 
locking  dog  is  stamped  with  the  number  of  the  tappet  with 
which  the  dog  is  to  engage  and  the  locking  bars  with  numbers 
to  correspond  with  the  slot  in  which  they  are  to  be  placed, 
these  slots  being  numbered  in  sequence  from  the  top  of  the 


186 


GENERAL  RAILWAY  SIGNAL  COMPANY 


CABINET 


FIG.  136.     MODEL,  2  UNIT  LEVER  TYPE  INTERLOCKING  MACHINE 


ELECTRIC  INTERLOCKING  HANDBOOK 


187 


FIG.  137.     MODEL  2  INTERLOCKING  MACHINE 


188 GENERAL  RAILWAY  SIGNAL  COMPANY 

locking  bed  to  the  bottom  (thirty-two  slots  per  tier  of  locking). 
Each  tappet  is  stamped  with  the  number  of  the  lever  to  which 
it  is  to  be  attached. 

The  levers  should  then  be  placed  in  their  respective  guides, 
and  worked  back  and  forth  to  insure  that  they  operate  freely, 
that  they  are  checked  at  the  normal  and  reverse  indication 
points,  and  that  they  can  be  moved  to  the  full  normal  and 
full  reverse  when  indicated.  (Signal  levers  are  not  indicated 
on  the  reverse  movement.)  The  circuit  controllers  and 
tappets  should  be  carefully  fastened  to  their  respective  levers, 
and  the  levers  tried  for  freedom  of  movement  with  all  working 
parts  connected. 

The  buss  bars,  buss  wires  and  the  connections  between  the 
individual  polarized  relays,  which  have  been  separated  during 
shipment,  should  be  securely  connected  by  joining  the  short 
leads  provided  on  the  machine  for  the  purpose. 

TESTING 

A  careful  test  should  be  given  to  the  mechanical  locking 
by  setting  up  the  various  routes  in  accordance  with  the  track 
plan  or  manipulation  chart,  testing  the  various  levers  in  the 
route  to  see  that  they  are  locked  and  likewise  testing  all  levers 
which  conflict  with  the  given  route.  This  will  insure  that 
none  of  the  locking  parts  have  been  omitted  in  assembling. 

When  wiring  up  the  interlocking  machine  it  is  well  to  check 
up  the  controller  contacts  to  see  that  all  special  contacts 
called  for  by  the  wiring  plans  have  been  provided. 

The  lever  and  its  connections  will  be  checked  up  as  the 
individual  functions  are  tested  out;  i.  e.,  the  completed  opera- 
tion of  the  function  normal  and  reverse,  shows  that  the  lever 
wiring  is  correct,  its  controller  springs  making  good  contact, 
that  the  indication  magnet  operates  properly,  and  if  the  func- 
tion is  a  switch,  that  the  indication  selector  also  is  giving 
proper  operation.  If  desired,  a  check  can  be  secured  on  the 
polarized  relays  by  making  the  cross  protection  tests  described 
on  page  94. 

MAINTENANCE 

The  maintenance  of  the  interlocking  machine  principally 
consists  in  keeping  the  machine  cleaned,  all  connections  tight, 
and  of  wiping  with  an  oiled  rag  at  stated  intervals  such  parts 
as  are  liable  to  rust. 

When  cleaning  or  oiling  the  locking,  it  should  not  be  re- 
moved from  the  interlocking  machine.  Use  only  high-grade 
oils,  such  as  "3  in  One,"  "Hydrol"  or  "Polar  Ice." 

Commercial  fuse  wire  should  not  be  used  to  replace  the  fuses 
furnished  with  the  machine,  since  commercial  wire  is  not 
carefully  graded  and  may  carry  a  much  larger  current  without 
melting  than  the  fuses  secured  from  the  manufacturer. 

As  a  general  statement,  it  may  be  said  that  the  operation  of 
the  various  functions  is  a  good  check  on  the  condition  of  the 


ELECTRIC  INTERLOCKING   HANDBOOK 


189 


interlocking  machine,  since  the  completed  operation  of  the 
various  functions  gives  assurance  as  to  the  integrity  of  all  parts 
of  their  operating  circuits.  It  is  well,  nevertheless,  to  antici- 
pate the  possibility  of  loose  connections,  etc.,  and  at  stated 
intervals  to  make  inspections  of  the  different  connections, 


FIG.  138.     MODEL,  2  UNIT  LEVER  TYPE  INTERLOCKING  MACHINE. 

EQUIPPED  WITH  SPRING  COMBINATION  BOARD 
Note  location  of  polarized  relays,  buss  bars  and  fuses. 

contacts  and  various  mechanical  parts  on  the  interlocking 
machine  to  insure  that  all  parts  are  kept  in  the  best  condition. 
As  mentioned  above,  the  operator  may  assure  himself  as  to 
the  constant  integrity  of  the  cross  protection  by  means  of  the 
simple  tests  described  on  page  94. 


190 


GENERAL  RAILWAY   SIGNAL  COMPANY 


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ELECTRIC   INTERLOCKING   HANDBOOK 


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INSTRUCTIONS  FOR  CUTTING  AND  TESTING 

NOTCHES  FOR  LEVERS  CONTROLLED 

BY  LEVER  LOCKS 

WHERE  lever  locks  are  applied  to  machines  before  ship- 
ment from  the  factory,  the  notches  are  cut  in  the 
levers  as  nearly  right  as  possible,  it  being  understood 
that  before  the  machines  are  put  into  service  on  the  ground 
the  clearance  will  again  be  checked  up  by  test  and  the 
notches  cut  out  further,  if  necessary,  to  give  the  proper  clear- 
ance. This  clearance  should  be  at  least  equal  to  that  indi- 
cated below  when  the  lever  in  question  is  locked  by  other 
levers  through  the  medium  of  the  tappet  locking,  and  also 
when  said  lever  is  pulled  or  pushed  hard  in  either  direction 
to  take  up  all  lost  motion,  the  lever  latch  being  lifted  at  the 
time. 

The  lever  should  be  tested  as  above  for  clearance  for  every 
combination  that  locks  it. 

In  making  the  test  for  clearance,  proceed  as  follows: 

With  the  lever  full  normal  (Fig.  139),  set  up  some  one  com- 
bination that  locks  it;  lift  lever  lock  (A)  by  applying  current, 
also  the  lever  latch  (B),  and  pull  the  lever  strongly  toward  the 
reverse  position,  as  indicated  by  the  arrow,  thus  taking  up  all 
lost  motion,  and  then  with  a  scriber  mark  this  position  of  the 
lever.  Then  drop  the  lever  lock  by  cutting  off  the  current, 
release  mechanical  locking  that  is  holding  the  lever,  and  again 
pull  the  lever  toward  the  reverse  position  until  it  takes  up 
against  the  lever  lock,  and  again  mark  the  position  of  the  lever 
with  a  scriber.  The  distance  between  these  scriber  marks 
will  then  tell  the  clearance  "D  "  existing.  Repeat  this  process 
for  every  combination  that  locks  the  lever  in  its  normal  posi- 
tion, and  if  the  clearance  "D"  thus  found  is  less  than  one- 
eighth  inch,  the  notch  in  the  lever  is  to  be  cut  out  further  to 
give  the  proper  clearance. 

Then  with  the  lever  full  reverse  (Fig.  140),  set  up  some  one 
combination  that  locks  it ;  lift  lever  lock  (A)  by  applying  cur- 
rent to  it,  also  the  lever  latch  (B),  and  push  the  lever  strongly 
toward  the  normal  position  as  indicated  by  the  arrow,  thus 
taking  up  all  lost  motion,  and  then  with  a  scriber  mark  this 
position  of  the  lever.  Then  drop  the  lever  lock  by  cutting  off 
the  current,  release  the  mechanical  locking  that  is  holding  the 
lever,  and  again  push  the  lever  toward  the  normal  position  until 
it  takes  up  against  the  lever  lock,  and  again  mart  the  position 
of  the  lever  with  a  scriber.  The  distance  between  the  two 
scriber  marks  will  then  tell  the  clearance  "D "  existing  for  the 
reverse  position  of  the  lever.  Repeat  this  process  for  every 
combination  that  locks  the  lever  in  its  reverse  position,  and 
if  the  minimum  clearance  "D"  thus  found  is  less  than  three- 
sixteenths  inch,  the  notch  in  the  lever  is  to  be  cut  out  further 
to  give  the  proper  clearance. 


ELECTRIC   INTERLOCKING   HANDBOOK 


193 


Tests  must  also  be  made  to  determine  that  the  clearance  (C) 
is  sufficient  to  permit  the  lock  to  drop  into  its  notch  when  the 
lever  is  pushed  as  far  normal  as  it  is  possible  to  get  it,  or  is 
pulled  as  far  reverse  as  it  is  possible  to  pull  it.  This  clearance 
"C"  can  be  checked  by  causing  the  lock  plunger  to  be  raised 


LEVER  LATCH  B 

FIXED  STOP  FOR  LEVER  LATCH  *& 

LOCK  PLUNDER "A" 

IXEO  GUIDE  FOR  LOCK  PLUNGER  V 
REVERSE  NOTCH 


-TAPPET  BAR 

FIG.  139.     NOTCHING  OF  LEVER  FOB  LEVER  LOCK.     NORMAL  POSITION 


FIXED  OUIOE  FOR  LOCK  PLUN6ER  "A* 
LOCK  PLUNGER  A* 


FIXED  GUIDE  FOR  TAPPET  BAR 
TAPPET  BAR 

FIG.  140.     NOTCHING  OF  LEVER  FOR  LEVER  LOCK.     REVERSE  POSITION 


and  lowered,  by  making  and  breaking  the  circuit  thus  applying 
energy  to  the  lock,  and  if  the  plunger  drops  into  the  notch  it 
is  known  that  the  clearance  is  there. 

In  cutting  the  notches  see  that  the  corners  are  left  square 
and  the  surface  that  comes  against  the  lock  plunger  is  vertical, 
so  that  there  may  be  no  tendency  to  force  the  lock  plunger  out 
by  pulling  hard  on  the  lever. 


194 


GENERAL  RAILWAY  SIGNAL  COMPANY 


Test  each  lock  by  putting  on  and  taking  off  current  several 
times  to  see  that  it  works  properly.  If  proper,  its  operation 
will  be  quick  and  sharp. 

Interlocking  levers  should  be  tested  periodically  when  in 
service,  in  accordance  with  above  instructions,  to  see  that 
sufficient  clearance  exists  between  the  lock  plunger  and  the 
notch  in  the  lever. 

It  will  be  sufficient  if  above  inspection  is  made  once  a  year. 

When  lever  locks  are  applied  to  interlocking  machines  after 
they  have  been  installed  it  is  sometimes  necessary  to  get 
additional  clearance  between  the  lock  plunger  and  the  lever 
guides.  This  is  to  prevent  the  plunger  from  sticking  to  the 
lever  guides  when  the  lock  is  energized. 

The  lever  guide  should  be  marked  and  chipped  where 
necessary,  so  that  no  part  of  the  lever  guide  will  be  closer  to 
the  plunger  than  one-eighth  inch. 

The  chipping  should  be  done  with  a  light  hammer  and  a 
small  cape  chisel,  and  every  precaution  should  be  taken  to 
prevent  the  chips  of  iron  from  getting  into  the  indication  mag- 
net coils. 


ENERGY    DATA    FOR    INDICATION    MAGNETS    FOR    MODEL    2 
INTERLOCKING    MACHINE 


FOR  SATISFACTORY  OPERATION 

Indication 
Magnet  for 

Ohms 
Resis. 

Should  Indicate  on 

Should  not  Indicate  on 

Volts 

Amps. 

Volts 

Amps. 

Solenoid  Dwarf,  .    . 

800 

90 

.112 

50 

.0625 

Model  3  Signal,    .    . 

1.42 

1.85 

1.30 

1.28 

.90 

Model  2A  Signal,     . 

6.80 

3.06 

.45 

2.58 

.38 

L.  V.  Battery,  .    .    . 

13.60 

4.35 

.32 

3.40 

.25 

Switch  Machine,  .    . 

1.42 

1.85 

1.30 

1.28 

.90 

A.  C.  25  Cycles,  .    . 

7.00 

35 

A.  C.  60  Cycles,   .    . 

7.00 

85 

NOTE. —  Values  given  above  are  for  magnets  mounted  on  interlocking 
machine. 


ELECTRIC  INTERLOCKING  HANDBOOK 


195 


FIG.  141.     LEVER  LOCK  FOR  MODEL  2  INTERLOCKING  MACHINE 


ENERGY   DATA  FOR    LEVER    LOCKS   OPERATING   ON 
DIRECT   CURRENT 


Resistance 
Ohms 

Mil  Amps. 

Volts 

14.5 

360 

5.2 

35 

238 

8 

75 

173 

13 

120 

133 

16 

250 

120 

30 

1400 

46 

64 

1500 

53 

80 

NOTE. —  Values  given  in  above  table  are  the  minimum  on  which  the  lock 
will  operate.  Add  10  per  cent,  for  practical  operation.  Drop  away  cur- 
rent equals  23  per  cent,  of  the  minimum  operating  current. 


ENERGY  DATA  FOR  LEVER  LOCKS  OPERATING  ON 
ALTERNATING  CURRENT 


Resistance 
Ohms 

Frequency 

Volts 

35 

25  cycles 

25 

8.6 

60  cycles 

25 

NOTE. —  Values  given  in  above  table  are  the  minimum  on  which  the  lock 
will  operate.  Add  10  per  cent,  for  practical  operation.  Drop  away  voltage 
equals  50  per  cent,  of  the  minimum  operating  voltage. 


SECTION  VIII 


INSTALLATION  AND  OPERATING  DATA  FOR 
SWITCH   MECHANISMS 


COVERING  INSTRUCTIONS  FOR  IN- 
STALLATION AND  MAINTENANCE, 
ENERGY  FIGURES,  CLEARANCES 
REQUIRED,  DIMENSIONS,  TIE 
FRAMINGS,  STANDARD  LAYOUTS, 
AND  TYPICAL  CIRCUITS;  ALSO 
DATA  ON  DETECTOR  BAR  FIT- 
TINGS, SWITCH  CIRCUIT  CONTROL- 
LERS AND  BRIDGE  CIRCUIT 
CLOSERS 


INSTRUCTIONS    COVERING   THE    INSTALLA- 
TION  AND   MAINTENANCE   OF  THE 
MODEL  2  SWITCH  MACHINE 


A' 


STORING  MECHANISMS 

LL  mechanisms  and  motors  should  be  placed  right  side 
up  on  timbers  to  raise  them  above  the  ground.  The  pole 
changers  should  be  housed  in  a  dry  place. 

INSTALLATION 

In  making  the  installation,  the  first  operation  is  the  framing 
of  the  ties.  This  should  be  in  ^accordance  with  the  plan 
shown  by  Fig.  142.  All  slots  cut  into  the  ties  should  be  care- 
fully cleaned  of  dirt,  chips,  etc.,  before  the  tie  plate  is  put 
down  and  the  gearing  assembled.  ^ 

Unless  special  features  are  required,  all  holes  in  the  tie  plate 
are  drilled  before  leaving  the  factory,  with  the  exception  of 
those  for  the  toe  and  slide  plates.  These  should  be  so  located 


FIG.  142      TIE  FRAMING  FOR  MODEL  2  SWITCH  MACHINE 


200 


GENERAL  RAILWAY  SIGNAL  COMPANY 


M  N       0 


DETECTOR    BAR 
CONNECTION 


FIQ.  143.     MODEL  2  SWITCH  MACHINE 


Motor 

Pole  Changer 
Friction  Clutch 
Main  Gear 
Intermediate  Gear 
Cam  Crank 
Stud  on  Main  Gear 
Driving  Rod 


H  Lock  Crank 

/  Lock  Plunger 

J  Throw  Rod 

K  Lock  Rod 

L  Pole  Changer  Movement 

M  Pole  Changer  Connecting  Rod 

N  Detector  Bar  Driving  Link 

O  Pin 


ELECTRIC   INTERLOCKING   HANDBOOK 


201 


that,  when  the  slide  plates,  toe  plates,  and  rail  braces  are  in 
place,  the  proper  track  gauge  will  be  rigidly  maintained. 

The  various  parts  of  the  switch  machine,  with  the  exception 
of  the  locking  plunger,  should  then  be  assembled.  In  placing 
the  motor,  care  should  be  taken  to  secure  proper  alignment  of 
the  connection  between  the  motor  and  main  gear. 

The  throw  and  lock  rods  may  be  connected  at  this  time  and 
the  lock  plunger  holes  in  the  throw  rod  drilled.  The  lock  rod, 
however,  should  not  be  drilled  until  it  is  certain  that  the  track 
has  its  final  alignment  and  the  rail  braces  have  been  fitted, 
thus  insuring  that  there  will  be  no  change  in  the  relative 
position  of  the  switch  points  and  switch  mechanism.  Special 
care  should  be  taken  when  marking  the  lock  rod  to  see  that  the 
switch  points  are  brought  tightly  up  against  the  stock  rail. 
The  most  accurate  method  of  marking  the  rods  is  to  withdraw 
the  lock  plunger  and  to  insert  in  its  place  a  piece  of  steel 


FIG.  144  FIG.  145 

Fields  in  Series.  Fields  in  Multiple. 

WIRING  FOR  MOTORS,  MODEL  2  SWITCH  MACHINE 

tubing  having  an  outside  diameter  of  one  inch,  this  tube 
being  pointed  so  as  to  make  a  clear  cut  mark  on  the  surface  of 
the  rod.  After  putting  the  machine  in  service,  the  top  of  the 
lock  rod  should  be  notched  slightly,  as  shown  by  Pt,  P2,  P3  and 
P4  in  Fig.  146,  to  permit  of  a  quick  inspection  being  made  as 
to  its  accurate  adjustment. 

In  wiring  the  machine,  suitable  conduit  should  be  installed 
to  protect  the  wires  running  between  the  trunking  and  motor, 
and  the  motor  and  pole  changer. 

ADJUSTMENTS 

Before  making  any  adjustments  with  the  machine  wired  up, 
the  brushes  should  be  raised  from  the  motor  armature. 

It  is  necessary  that  the  detector  bar  be  disconnected  while 
making  adjustments  1  and  2. 

1.     Plunger  Connection. 

With  the  machine  placed  in  either  extreme  position  (that 
is  with  stud  F  at  either  end  of  the  stroke  in  cam  crank  E), 


202 


GENERAL  RAILWAY  SIGNAL  COMPANY 


the  driving  rod  G  should  be  adjusted  to  such  a  length  that  the 
end  of  lock  plunger  I  will  be  flush  with  the  outside  face  of  the 
lock  frame  (see  Fig.  146).  This  adjustment  never  varies,  and 
it  should  not  be  changed  after  once  being  made  correctly.  If 
incorrectly  made  it  is  liable  to  cause  indication  failure. 

2.    Pole  Changer  Movement. 

When  locating  pins  in  the  lock  rod  K  for  the  operation  of  the 
pole  changer  movement,  move  the  switch  machine  to  the 
extreme  position  as  shown  in  Fig.  143.  Locate  pin  Qt  so  that 
link  R  will  just  clear  cap  St  by  five-sixteenth  inch  (Fig.  146). 


FIG.  146.     POLE  CHANGER  MOVEMENT  L  FOR  MODEL  2  SWITCH 

MACHINE 

Lock  plunger  I  is  shown  at  end  of  its  travel  and  not  in  position  corre- 
sponding with  that  of  link  R. 

Then  throw  the  switch  to  the  other  extreme  position  and 
locate  pin  Q2  in  a  similar  manner.  When  assembling  the 
pins  on  the  lock  rod,  drill,  tap,  and  countersink  the  lock  rod  as 
shown  in  Fig.  148. 

3.    Pole  Changer  Connection. 

Any  lost  motion  between  the  pole  changer  movement  L  and 
the  pole  changer  B  must  be  equal  at  the  full  normal  and  full 
reverse  position  of  the  switch  machine.  To  secure  this,  adjust 
the  connecting  rod  M  with  the  switch  machine  in  either  of  its 
extreme  positions.  Test  with  the  machine  first  in  the  full 
normal  position  and  then  in  the  full  reverse  position,  pushing 


ELECTRIC   INTERLOCKING   HANDBOOK 


203 


and  pulling  the  rod  M  strongly  to  determine  the  total  distance 
it  is  possible  to  be  moved.  Repeat  the  adjustment  until  the 
desired  result  is  obtained.  This  adjustment  never  varies  in 
service  and  it  should  not  be  changed  after  once  being  made 
correctly.  If  it  is  not  made  correctly  it  is  very  liable  to  pre- 
vent the  indication  being  given  on  the  movement  of  the  switch 
to  the  position  where  the  greatest  lost  motion  exists. 

4.     Pole  Changer  Commutator. 

The  commutator  T  (Fig.  147)  must  revolve  freely  in  its 
bearings,  care  being  taken  that  the  contact  springs  Ulf  U2 
and  U3  do  not  have  so  much  tension  as  to  prevent  spring  V 
from  snapping  the  commutator  over.  Adjust  so  that  with 
machine  full  normal  or  reverse,  roller  W  and  pin  X  are  in  the 


£=] 


u 


V-7 

iis=S<- 

\\     & 

}  CONTROL  WIRES 

—   MAIN  COMMON 
FIG.  147.     POLE  CHANGER  WIRING,  MODEL  2  SWITCH  MACHINE 

relative  positions  shown.  The  adjustment  of  the  commutator 
must  be  such  that  the  snapping  action  will  take  place  at  such  a 
time  that  the  amount  of  movement  in  the  contact  blocks  Z, 
and  Z2,  which  precedes  the  snapping  action,  will  be  equal  for 
the  normal  or  reverse  movement.  To  be  certain  that  this 
result  is  obtained  it  will  be  necessary  to  move  the  mechanism 
a  number  of  times  by  hand  very  slowly.  Failure  to  have  the 
adjustment  right  will  be  almost  certain  to  result  in  damage  to 
the  insulating  cylinder,  due  to  arcing  between  the  contact 
spring  and  the  contact  cylinder,  and  may  prevent  indication. 

The  contact  springs  Ux  and  U3  are  provided  with  slots  which 
will  permit  the  springs,  when  resting  on  the  insulated  portion 
of  the  commutator,  to  be  centrally  located. 

After  the  commutator  adjustments  have  been  completed  and 
machine  worked  sufficiently  to  insure  correct  action,  remove 


204  GENERAL  RAILWAY  SIGNAL  COMPANY 


one  of  the  set  screws  from  the  collar  Y,  drill  into  the  shaft 
and  replace  the  screw,  running  it  down  until  it  locks  the  com- 
mutator to  its  shaft;  repeat  this  operation  with  the  other 
screw  located  in  the  collar. 

In  connecting  up  the  operating  coils  to  the  contact  springs 
Ui  and  U3,  be  sure  to  see  that  when  the  commutator  is  in  its 
full  normal  or  full  reverse  position,  the  contact  spring  which 
rests  on  the  metal  cylinder  does  not  carry  current.  This  can 
be  done  by  lifting  it  slightly;  if  a  spark  results  it  shows  that 
the  contact  springs  should  be  interchanged. 

5.  Throw  Rod. 

The  nuts  on  the  throw  rod  must  be  placed  so  that  the  switch 
points  will  be  brought  up  against  the  stock  rail  snugly,  but 
not  screwed  up  far  enough  to  put  any  unnecessary  strain  on  the 
rod.  Under  normal  conditions,  with  the  throw  rod  adjusted 
as  above,  a  single  switch  or  derail  should  permit  of  hand 
operation  (without  the  aid  of  a  wrench  or  tommy  bar)  by 
turning  the  intermediate  gear  Da.  If  it  is  not  possible  to  do 
this,  steps  should  be  taken  to  get  the  switch  into  this  condition. 

6.  Lock  Rod. 

The  drilling  of  the  lock  rod  should  be  such  that  the  lock 
plunger  will  enter  either  hole  with  the  switch  full  normal  or 
full  reverse,  but  will  be  prevented  from  entering  if  a  piece  of 
metal  one-eighth  of  an  inch  thick  is  placed  between  the  switch 
point  and  the  stock  rail. 

7.  Detector  Bar. 

To  adjust  the  detector  bar,  place  it  in  the  desired  position 
relative  to  the  top  of  the  rail  and  adjust  the  connection  N  to 
such  a  length  that  with  the  switch  machine  in  either  extreme 
position,  pin  O  may  be  inserted  without  changing  the  position 
of  either  the  detector  bar  or  switch  machine. 

8.  Clutch. 

The  nut  on  friction  clutch  C,  by  which  the  compression  of 
the  spring  is  increased  or  diminished,  should  be  locked  in  a 
position  which  will  enable  the  motor  to  operate  the  switch 
under  normal  conditions,  but  will  permit  the  clutch  to  slip  if 
there  is  an  obstruction  in  the  switch  points.  This  is  deter- 
mined by  starting  with  the  nut  unscrewed  and  gradually 
tightening  it  up  until  the  motor  operates  the  switch  without 
any  slipping  of  the  clutches. 

Before  any  adjustments  are  made  on  the  friction  clutch, 
separate  the  cones  from  the  pinion  and  oil  the  clutch  cones. 

TESTING 

The  preferred  method  of  testing  the  operation  of  the  switch 
mechanism  is  to  operate  it  by  hand,  making  sure  that  the  motor 
brushes  are  raised  before  attempting  to  move  the  machine. 
This  method  should  be  employed  as  a  regular  practice. 

If  it  should  become  necessary  to  operate  the  switch  by 
power,  the  tests  on  the  switch  machine  should  be  carried  on 
under  the  protection  of  the  operating  lever,  whenever  the 


ELECTRIC   INTERLOCKING   HANDBOOK  205 


conditions  are  such  that  the  leverman  can  readily  receive  and 
act  on  signals  given  him  by  the  man  on  the  ground. 

On  the  rare  occasions  when  it  is  not  practical  to  conduct 
the  test  under  the  control  of  its  lever,  power  may  be  applied 
locally  by  taking  both  control  wires  off  from  their  respective 
binding  posts  (for  contact  springs  U4  and  U«,  Fig.  147)  in  the 
pole  changer,  and  having  first  connected  spring  U2  with  a 
short  piece  of  wire  to  the  open  control  contact  spring  (spring 
U4,  Fig.  147),  current  may  be  sent  through  the  motor  by  plac- 
ing the  energized  control  wire  in  connection  with  the  other 
control  contact  spring  (spring  Us,  Fig.  147) ;  with  these  con- 
nections the  mechanism  will  be  brought  to  rest  upon  the  com- 
pletion of  its  movement  without  shock.  Reverse  these  con- 
nections to  secure  operation  in  the  opposite  direction. 

After  the  machine  is  completely  adjusted,  safety  requires 
that  it  should  be  operated  from  the  interlocking  station  sev- 
eral times,  making  sure  that  with  the  lever  in  its  normal  posi- 


FIG.  148.     DRILLING  FOR  PINS  Q»  AND  Q8  IN  LOCK  ROD  K 

tion  the  switch  points  will  correspond  with  their  position  as 
shown  on  the  track  plan. 

MAINTENANCE 

1.    Mechanism. 

When  inspecting  the  switch  machine  always  note  the  posi- 
tion of  the  lock  plunger  relative  to  the  face  of  lock  frame.  If 
it  is  not  flush  with  the  outside  face  of  the  lock  frame,  make 
sure  that  stud  F  is  in  the  corner  of  cam  crank  E.  With  the 
switch  adjusted  correctly  and  the  stud  F  at  the  end  of  its 
travel,  there  are  two  conditions  which  would  be  responsible 
for  the  plunger  not  reaching  its  proper  position. 

First  —  The  rails  may  have  shifted  and  altered  the  throw 
of  the  switch  points,  which  will  put  an  unusual  strain  on  the 
switch  machine  and  prevent  the  full  movement  of  the  lock 
plunger.  This  will  be  determined  by  operating  the  switch  by 
hand. 

Second  —  The  detector  bar  may  have  been  thrown  out  of 
adjustment  by  the  shifting  of  the  rails,  this  preventing  the 
generation  of  the  indication  current.  Necessity  for  readjust- 
ment is  determined  by  disconnecting  the  bar,  placing  it 
in  proper  position  and  the  switch  machine  in  either  extreme 
position;  if  it  is  not  possible  to  replace  the  pin  O  without 


206  GENERAL  RAILWAY  SIGNAL  COMPANY 


moving  either  the  machine  or  detector  bar,  the  connections 
should  be  readjusted. 

On  each  inspection  examine  the  friction  clutch  to  see  that  it 
slips  properly  on  overload. 

2.  Motor. 

The  motor  commutator  or  brushes  should  not  be  disturbed 
unless  found  necessary.  If  the  commutator  becomes  dirty,  it 
should  be  cleaned  with  chamois  skin  moistened  with  oil,  any 
surplus  oil  being  wiped  off  the  commutator  by  a  dry  piece  of 
chamois. 

If  it  becomes  necessary  to  put  a  new  brush  into  a  motor, 
the  brush  after  being  put  in  position  should  be  seated  to  the 
commutator  by  drawing  thin,  fine  sandpaper  under  the  brush, 
at  the  same  time  pressing  the  brush  against  the  commutator; 
the  smooth  side  of  the  sandpaper  should  be  against  the  com- 
mutator. Use  for  this  purpose  "00  Single  Finishing  Flint 
Sandpaper." 

3.  Small  Parts. 

All  cotter  pins,  lock  washers,  binding  posts,  small  nuts  and 
screws,  should  be  inspected  at  stated  intervals  to  see  that  they 
are  not  working  loose. 

4.  Contact  Surfaces. 

The  pole  changer  contacts  should  be  kept  clean  and  bright. 

5.  Oil 

Moving  parts  not  exposed  to  the  weather  should  be  well 
oiled  once  a  month.  All  parts,  the  bearing  surfaces  of  which 
can  be  reached  by  rain,  should  be  oiled  immediately  after  each 
storm.  The  friction  clutches  should  be  oiled  on  each  inspec- 
tion trip. 


INSTRUCTIONS    COVERING   THE    INSTALLA- 
TION AND  MAINTENANCE   OF  THE 
MODEL  4  SWITCH  MACHINE 
STORING  MECHANISMS 

An,L  mechanisms  and  motors  should  be  placed  right  side  up 
on  timbers  to  raise  them  above  the  ground. 

INSTALLATION 

In  making  the  installation,  the  first  operation  is  the  framing 
of  the  ties.  This  should  be  in  accordance  with  the  plan 
shown  by  Fig.  149. 

Unless  special  features  are  required,  all  holes  in  the  tie  plate 


Tie  H9  2 


=* 

-4- 


11 


Tie 


1    =m    y 

Tie  H?2 

~g 

^ 

l   .  t 

-if 

""igr  —  '-!»" 

Tie  H9  j 

Is 

II1-  0"  > 

Fia.  149.    TIE  FKAMINO  FOB  MODEL  4  SWITCH  MACHINE 
Ties  to  be  cut  as  shown  in  dotted  lines  for  electrified  roads  using  third  rail. 


208 


GENERAL  RAILWAY   SIGNAL  COMPANY 


Motor 
Intermediate  Gear 

Friction  Clutch 

Main  or  Cam  Gear 

Roller  on  Main  Ge 

Locking  Bar 

i-G,  Rollers  on  Lockinj 

\-H9  Locking  Dogs 
Lock  Rod 

Throw  Rod 

H 
d 

5 

Locking  Bolt 

f  Pole  Changer 
Tripper  Arm 

Switch  Circuit  Con 
Location 

ELECTRIC   INTERLOCKING   HANDBOOK  209 

are  drilled  before  leaving  the  factory,  with  the  exception  of 
those  for  the  toe  and  slide  plates.  These  should  be  so  located 
that  when  the  slide  plates,  toe  plates,  and  rail  braces  are  in 
place,  the  proper  track  gauge  will  be  rigidly  maintained. 

The  switch  machine  should  then  be  bolted  down  to  the  tie 
plate  and  the  throw  and  lock  rods  connected. 

ADJUSTMENTS 

As  the  switch  machine  is  completely  assembled  in  the  factory 
and  all  parts  adjusted  to  meet  the  conditions  under  which  the 
mechanism  is  to  operate,  there  is  very  little  in  the  way  of 
adjustments  necessary  to  be  made. 

After  the  machine  is  wired  up,  before  making  any  adjust- 
ments which  may  be  required,  the  brushes  should  be  raised 
from  the  motor  armature. 

1.     Throw  Rod. 

The  nuts  on  the  throw  rod  must  be  placed  so  that  the  switch 
points  will  be  brought  up  against  the  stock  rail  snugly,  but 
not  screwed  up  far  enough  to  put  any  unnecessary  strain  on 


FIG.  151  FIG.  152 

Fields  in  Series.  Fields  in  Multiple. 

WIRING  FOB  MOTORS,  MODEL  4  SWITCH  MACHINE 

the  rod.  Under  normal  conditions,  with  the  throw  rod  adjusted 
as  above,  a  single  switch  or  derail  should  permit  of  hand 
operation,  by  using  the  crank  provided  for  the  purpose.  If  it 
is  not  possible  to  do  this,  steps  should  be  taken  to  get  the 
switch  into  this  condition. 

2.  Lock  Rod. 

The  adjustment  of  the  lock  rod  should  be  such  that  the 
locking  dog  Hj  or  H3  will  enter  its  proper  notch  in  the  lock 
rod  I  with  the  switch  full  normal  or  full  reverse",  as  the  case 
may  be,  but  will  be  prevented  from  entering  if  a  piece  of  metal 
one-eighth  of  an  inch  thick  is  placed  between  the  switch 
point  and  the  stock  rail. 

3.  Detector  Bar. 

To  adjust  the  detector  bar,  place  it  in  the  desired  position 
relative  to  the  top  of  the  rail  and  adjust  the  connections  to 
such  a  length  that  with  the  switch  machine  in  its  extreme 
position,  pin  P  may  be  inserted  without  changing  the  position 
of  either  the  detector  bar  or  switch  machine.  Check  this 
adjustment  with  the  bar  and  switch  machine  in  the  opposite 
position  and  readjust  if  necessary. 


210 


GENERAL  RAILWAY  SIGNAL  COMPANY 


4.     Clutch. 

The  nut  on  friction  clutch  C,  by  means  of  which  the  com- 
pression of  the  spring  is  increased  or  diminished  should  be 
locked  in  a  position  which  will  enable  the  motor  to  operate 
the  switch  under  normal  conditions,  but  will  permit  the 
clutch  to  slip  if  there  is  an  obstruction  in  the  switch  points. 
This  is  determined  by  starting  with  the  nut  unscrewed  and 
gradually  tightening  it  up,  until  the  motor  operates  the  switch 
without  any  slipping  of  the  clutches. 


L . nirUjlIL  ~.l}  CONTROL  Huwa 

• 4. MAIN  COMMON 


MAIN  COMMON, 
FIG.  153.     POLE  CHANGER  WIRING,  MODEL,  4  SWITCH  MACHINE 

TESTING 

The  preferred  method  of  testing  the  operation  of  the  switch 
mechanism  is  to  operate  it  by  hand  by  means  of  the  crank 
provided  for  this  purpose,  first  making  sure  that  the  motor 
brushes  are  raised  before  attempting  to  move  the  machine. 
This  method  should  be  employed  as  a  regular  practice. 

If  it  should  become  necessary  to  operate  the  switch  by 
power,  the  tests  on  the  switch  machine  should  be  carried  on 
under  the  protection  of  the  operating  lever,  whenever  the  con- 
ditions are  such  that  the  leverman  can  receive  and  act  on 
signals  given  him  by  the  man  on  the  ground. 

On  the  rare  occasions  when  it  is  not  practical  to  conduct 
the  test  under  the  control  of  its  lever,  power  may  be  applied 
locally  by  taking  both  control  wires  off  from  their  respective 
binding  posts  (for  contact  springs  Qt  and  Q2,  Fig.  153)  in  the 
pole  changer,  and  having  first  connected  common  post  R 
with  a  short  piece  of  wire  to  the  open  control  contact  spring 


ELECTRIC  INTERLOCKING  HANDBOOK  211 


(spring  Qi,  Fig.  153),  current  may  be  sent  through  the  motor 
by  placing  the  energized  control  wire  in  connection  with  the 
other  control  contact  spring  (spring  Qa,  Fig.  153) ;  with  these 
connections  the  mechanism  will  be  brought  to  rest  without 
shock  upon  the  completion  of  its  movement.  Reverse  these 
connections  to  secure  operation  in  the  opposite  direction. 

After  the  machine  is  completely  adjusted,  safety  requires 
that  it  should  be  operated  from  the  interlocking  station  several 
times,  making  sure  that  with  the  lever  in  its  normal  position, 
the  switch  points  will  correspond  with  their  position  as  shown 
on  the  track  plan. 

MAINTENANCE 

1.  Mechanism. 

Shifting  of  the  rails  may  prevent  correct  operation  of  the 
switch  machine  in  the  following  manner : 

First  —  By  altering  the  throw  of  the  switch  points,  an 
unusual  strain  will  be  put  on  the  switch  machine  which  will 
prevent  the  mechanism  from  locking  up.  This  will  be  deter- 
mined by  operating  the  switch  by  hand. 

Second  —  The  detector  bar  may  have  been  thrown  out  of 
adjustment,  this  preventing  the  generation  of  the  indication 
current.  Necessity  of  readjustment  is  determined  by  dis- 
connecting the  bar,  placing  it  in  proper  position  and  the 
switch  machine  in  its  corresponding  extreme  position;  if  it  is 
not  possible  to  replace  the  pin  P  without  moving  either  the 
machine  or  detector  bar,  the  connections  should  j?  readjusted. 

2.  Motor. 

The  motor  commutator  or  brushes  should  not  be  disturbed 
unless  found  necessary.  If  the  commutator  becomes  dirty, 
it  should  be  cleaned  with  chamois  skin  moistened  with  oil, 
any  surplus  oil  being  wiped  off  the  commutator  by  a  dry  piece 
of  chamois. 

If  it  becomes  necessary  to  put  a  new  brush  into  a  motor, 
the  brush  after  being  put  in  position  should  be  seated  to  the 
commutator  by  drawing  thin,  fine  sandpaper  under  the  brush, 
at  the  same  time  pressing  the  brush  against  the  commutator; 
the  smooth  side  or  the  sandpaper  should  be  against  the  com- 
mutator. Use  for  this  purpose  "00  Single  Finishing  Flint 
Sandpaper." 

3.  Small  Parts. 

All  cotter  pins,  lock  washers,  binding  posts,  small  nuts  and 
screws,  should  be  inspected  at  stated  intervals  to  see  that  they 
are  not  working  loose. 

4.  Contact  Surfaces. 

The  switch  circuit  controller  and  pole  changer  contacts 
should  be  kept  clean  and  bright. 

5.  Oil 

Moving  parts  not  exposed  to  the  weather  should  be  well 
oiled  once  a  month.  All  parts,  the  bearing  surfaces  of  which 
can  be  reached  by  rain,  should  be  oiled  immediately  after  each 
storm. 


212 


GENERAL  RAILWAY  SIGNAL  COMPANY 


r 


it 

i 


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-i 


_i 


j 


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E 


ill 


S  5      5 


"3  ^3*    o 
P^  .«  .-^ 


O 

_:    S 


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P4    O          fc;    o  »    O 


=  tf 


ELECTRIC   INTERLOCKING  HANDBOOK 


213 


- 
ii  Irlli  If 


214 


GENERAL  RAILWAY  SIGNAL  COMPANY 


OPERATING   DATA   FOR   SWITCH   MACHINES 


Operating 

Time 

Function  Operated 

Operating 
Current 

Using 
Maximum 
Length 

Control 

Wires 

Amp. 

Seconds 

Switch  Machine,  Model  2,  Switch  or  Derail,     .    .    . 

6.0 

2 

Switch  Machine,  Model  2,  Double  Slip  or  M.  P. 

Frog                                                                     .    . 

10.0 

2.2 

Switch  Machine,  Model  4A,  Switch  or  Derail,  .    .    . 

4.5 

3 

Switch  Machine,  Model  4A,  Double  Slip  or  M.  P. 

Frog,  

7.0 

3.2 

Switch  Machine,  Model  4B,  Switch  or  Derail,.    .    . 

4.5 

3 

Switch  Machine,  Model  4B,  Double  Slip  or  M.  P. 

Frog                                                                        .    .    . 

7.0 

3.2 

FIG.  156.     DIAGRAM  SHOWING  COMPARATIVE  CLEARANCES  OF  MODEL,  2 

AND  MODEL  4  SWITCH  MACHINE 

Normal  location. 


DIMENSION  A  MODEL  2  SWITCH  MACHINE 

Rail  Section 

(See  Note.) 

A.  R.  A.  —  Type  A. 

A.  R.  A.—  Type  B. 

A.  S.  C.  E. 

Lbs.  per  Yd. 

Inches 

Inches 

Inches 

60 

22% 

21 

21% 

70 

23% 

22%6 

228/4 

80 

24% 

24 

24% 

90 

26% 

25%6 

25% 

100 

28% 

26i%0 

27% 

NOTE. —  Dimension  A  is  the  distance  from  gauge  side  of  rail  to  point  on 
cover  of  Model  2  switch  machine  equal  to  height  of  rail  used. 


ELECTRIC   INTERLOCKING   HANDBOOK 


215 


FIG.  157.     DIAGRAM  SHOWING  CLEARANCE  BETWEEN  TOP  OF  MODEL  4 

SWITCH  MACHINE  AND  CONTACTING  SURFACE  OF  THIRD  RAIL. 

ELECTRIC  DIVISION,  N.  Y.  C.  &  H.  R.  R.  R. 


Ij^fepj^ 

jr 

(— 

J   h 

I      I 

J 

/ 

t 

FIG.  158.     DIAGRAM  SHOWING  CLEARANCE  BETWEEN  TOP  OF  MODEL  4 

SWITCH  MACHINE  AND  CONTACTING  SURFACE  OF  THIRD  RAIL, 

LONG  ISLAND  R.  R. 


216 


GENERAL  RAILWAY  SIGNAL  COMPANY 


.    I F"'T--''..fT7.ii6 

\  Circular  loom/ 


;oj '-* "  '  j.  Conn etion,    j>    "10100 

"**— ^io;       ~-3y>--^   C     £ 


Fio.  159.     DIMENSIONS  OF  MODEL  2  SWITCH  MACHINE 


ELECTRIC  INTERLOCKING  HANDBOOK 


217 


e'4 «i" •[- 


FIG.  160.     DIMENSIONS  OF  MODEL  4  SWITCH  MACHINE  FOR  MOVABLE 
POINT  FBOQ  OR  DOUBLE  SLIP  SWITCH 


Fio.  161      DIMENSIONS  OF  MODEL  4  SWITCH  MACHINE  FOR  SINGLE 
SWITCH  OR  DERAIL 


218 


GENERAL  RAILWAY  SIGNAL  COMPANY 


(Section  A-B) 
FIG.  162.     SINGLE  SWITCH  OPERATED  BY  MODEL  4  SWITCH  MACHINE 


(Section  A-B) 
FIG.  163.     SINGLE  SWITCH  OPERATED  BY  MODEL  2  SWITCH  MACHINE 


ELECTRIC  INTERLOCKING   HANDBOOK 


219 


(Section  A-B) 

FIG.  164.     SPLIT  POINT  DERAIL  OPERATED  BY  MODEL  4 
SWITCH  MACHINE 


(Section  A-B) 

Fia.  165.     SPLIT  POINT  DERAIL  OPERATED  BY  MODEL  2  SWITCH 
MACHINE 


220 


GENERAL,  RAILWAY  SIGNAL  COMPANY 


ffi 


2-8— 


(Section  A-B) 
FIG.  166.     HAYES  DERAIL  OPERATED  BY  MODEL  4  SWITCH  MACHINE 


(Section  A-B) 
FIG.  167.     HAYES  DERAIL  OPERATED  BY  MODEL  2  SWITCH  MACHINE 


ELECTRIC   INTERLOCKING   HANDBOOK 


221 


(Section  A-B) 

FIG.  168.     WHARTON  OR  MORDEN  DERAIL  OPERATED  BY  MODEL  4 
SWITCH  MACHINE 


(Section  A-B) 

FIG.  169.     WHARTON  OR  MORDEN  DERAIL  OPERATED  BY  MODEL  2 
SWITCH  MACHINE 


222  GENERAL  RAILWAY   SIGNAL  COMPANY 


(Section  A-B) 

FIG.  170.     SINGLE  SLIP  SWITCH  OPERATED  BY  MODEL  4  SWITCH 
MACHINE 


(Section  A-B) 

FIG.  171.     SINGLE  SLIP  SWITCH  OPERATED  BY  MODEL  2  SWITCH 
MACHINE 


ELECTRIC   INTERLOCKING   HANDBOOK 


223 


(Section  A-B) 

FIG.  172.     DOUBLE  SLIP  SWITCH  OPEKATED  BY  MODEL  4  SWITCH 
MACHINE 


(Section  A-B) 

FIG.  173.     DOUBLE  SLIP  SWITCH  OPERATED  BY  MODEL  2  SWITCH 
MACHINE 


224 


GENERAL  RAILWAY  SIGNAL  COMPANY 


(Section  A-B) 

FIG.  174.     MOVABLE  POINT  FROG  OPERATED  BY  MODEL  4 
SWITCH  MACHINE 


(Section  A-B) 

FIG.  175.     MOVABLE  POINT  FROG  OPERATED  BY  MODEL  2  SWITCH 
MACHINE 


ELECTRIC  INTERLOCKING   HANDBOOK 


225 


(Section  A-B) 

FIG.  176.     MOVABLE  POINT  FROG  (WITH  DOUBLE  SLIP  SWITCH) 
OPERATED  BY  MODEL  4  SWITCH  MACHINE 


A-- 


(Section  A-B) 

FIG.  177.     MOVABLE  POINT  FROG  (WITH  DOUBLE  SLIP  SWITCH) 
OPERATED  BY  MODEL  2  SWITCH  MACHINE 


226 


GENERAL  RAILWAY  SIGNAL  COMPANY 


§1- 

^ 

.y  o> 

c  ^ 
£  <n 


ELECTRIC   INTERLOCKING   HANDBOOK 


227 


QJ 

<n 


228 


GENERAL  RAILWAY  SIGNAL  COMPANY 


ELECTRIC   INTERLOCKING   HANDBOOK 


229 


HOOK  BOLT  — 3| 

FIG.  181.     E.  Z.  MOTION  PLATE  RAIL  CLIP,  HOOK  BOLT  TYPE 


FIG.  182.     E.  Z.  MOTION  P^ATE  RAIL  CLIP,  WEB  BOLT  TYPE 


FIG.  183.     LONG  MOTION 
PLATE  "A" 


FIG.  184.     SHORT  MOTION 
PLATE  "B" 


DIMENSIONS   OF   MOTION   PLATES  "A"  AND  "B1 


DIMENSIONS  IN  INCHES 

C 

D 

E 

F 

G 

Type  of 

Distance  Mo- 

Motion 
Plate 

Overall 
Length  of 
Motion 
Plate 

Stroke  of 
Motion 
Plate 

tion  Plate 
Moves  After 
Total  Rise 
Above  Rail 

Total  Rise 
of  Motion 
Plate 

Rise 
Above 
Rail 

*A 

9y2 

6 

2 

1 

% 

tA 

12 

7% 

3Va 

1 

% 

tA 

i2ya 

sya 

2% 

l7/ie 

1%6 

*B 

oys 

4% 

1%2 

2%2 

tB 

ioy2 

6 

•• 

Uft 

VA 

*  Two  rivet  holes,     f  Three  rivet  holes. 


230 


GENERAL  RAILWAY  SIGNAL  COMPANY 


ELECTRIC   INTERLOCKING   HANDBOOK 


231 


FIG.  186.     DIMENSIONS  OF  MODEL  5  FORM  A  SWITCH  CIRCUIT 
CONTROLLER  FOR  SELECTING  SIGNAL  CIRCUITS 

Four  circuits  normal  or  reverse,  or  two  circuits  normal 
and  two  reverse. 


FIG.  187.  SECTION  OF  ADJUSTA- 
BLE CAM  FOR  MODEL  5  FORM  A 
SWITCH  CIRCUIT  CONTROLLER  (Fio. 
186). 


232  GENERAL  RAILWAY  SIGNAL  COMPANY 


FIG.  188 


Fia.  189 


Fia.  190 


FIG.  191 


Flo.  192 


Fia.  193 


FIG.  194 


CONNECTIONS  FROM  SWITCH  POINT  TO  SWITCH  CIRCUIT  CONTROLLER 


ELECTRIC   INTERLOCKING   HANDBOOK 


233 


Bridge  End  Shore  End 

FIG.  195.     BRIDGE  CIRCUIT  CLOSER 
Ten  way,  controlling  ten  circuits. 

DIMENSIONS   OF   BRIDGE   CIRCUIT   CLOSERS 


A 

B 

c 

D 

E 

F 

G 

H 

J 

K 

L 

M 

In. 

In. 

In. 

In. 

In. 

In. 

In. 

In. 

In. 

In. 

In. 

In. 

6  way 

18* 

6f 

14| 

2 

4* 

1H 

144 

19 

| 

7i 

U 

10  way 

26 

7 

221 

8 

4ft 

12ft 

22 

24* 

H 

1 

8J 

41 

12  way 

18* 

lift 

141 

2 

4* 

io« 

14* 

19 

; 

7* 

If 

NOTE. — Twelve  way  circuit  closer  is  furnished  with  two  tiers  of  six  con- 
tacts each. 

OPERATION  OF  BRIDGE  CIRCUIT  CLOSER 

The  G.  R.  S.  bridge  circuit  closer  with  centering  device  is 
shown  in  Fig.  195.  In  the  operation  of  closing,  the  bridge 
end  is  first  caused  to  approach  the  shore  end  with  its  centering 
arms  thrust  forward.  When  these  come  into  contact  with  the 
shore  end,  the  latter  is  brought  into  proper  alignment,  the 
bridge  end  continuing  its  forward  movement  until  they  abut ; 
the  blades  are  then  forced  to  enter  the  jaws,  thus  making  the 
desired  contact. 

The  centering  device  will  take  care  of  any  horizontal  mis- 
alignment up  to  one  and  one-half  inches.  When  this  is 
apt  to  be  exceeded,  the  circuit  closer  should  be  attached  to 
the  rails  in  such  a  manner  that  when  the  rails  are  lined  up 


234  GENERAL  RAILWAY  SIGNAL  COMPANY 


the  circuit  closer  will  be  affected  in  a  similar  manner.  The- 
design  of  the  jaws  permits  of  three-fourths  inch  movement 
above  or  below  the  normal  position. 

The  maximum  stroke  of  the  driving  member  is  approxi- 
mately thirteen  inches.  Using  this  stroke,  the  maximum 
extension  of  the  blades  (three  and  one-half  inches)  can  be 
secured  with  a  permissible  opening  of  five  and  three-eighths 
inches  between  the  bridge  and  shore  ends  of  the  circuit  closer ; 
this  forces  the  blades  between  the  jaws  two  and  three-eighths 
inches.  If  required,  this  distance  between  the  bridge  and 
shore  ends  may  be  increased  to  seven  and  three-sixteenths 
inches,  which  will  give  a  contact  extension  of  one  and  thir- 
teen-sixteenths  inches  and  force  the  blades  between  the  jaws 
for  a  distance  of  three-fourths  inch. 

If  it  is  desired  to  reduce  the  operating  stroke  and  still  retain 
the  maximum  contact  extension,  the  maximum  opening  be- 
tween the  bridge  and  shore  ends  must  be  decreased  a  propor- 
tional amount. 


SECTION   IX 


INSTALLATION  AND  OPERATING  DATA  FOR 
SIGNAL  MECHANISMS 


COVERING  INSTRUCTIONS  FOR  IN- 
STALLATION AND  MAINTENANCE,  EN- 
ERGY FIGURES,  CLEARANCES  RE- 
QUIRED, DIMENSIONS  AND  TYPICAL 
CIRCUITS;  ALSO  DIMENSIONS  OF 
MASTS,  SPECTACLES,  BLADES  AND 
FOUNDATIONS 


INSTRUCTIONS  COVERING  THE   INSTALLA- 
TION   AND    MAINTENANCE    OF 
MODEL  2A  SIGNALS 

STORING  MECHANISMS 

A*L  mechanisms  should  be  stored  in  an  upright  position 
and,  if  possible,  in  a  dry  place,  and  should  not  be  re- 
moved from  their  boxes  until  they  are  installed.     Avoid 
disconnecting  or  removing  the  motors  from  the  mechanism 
cases. 

INSTALLATION 

In  assemblying  mechanisms  which  are  shipped  separately 
from  the  pole  bearings  or  in  reassemblying  mechanisms  which 
have  been  disassembled  for  any  purpose,  the  surface  of  all 
exposed  mechanical  joints  must  be  cleaned  and  smoothly 
coated  with  white  lead  before  assembly,  to  insure  that  they 
are  water-tight. 

Whenever  it  becomes  necessary  to  bolt  a  mechanism  to  its 
pole  bearing,  see  that  the  semaphore  shaft  and  mechanism 
are  approximately  in  their  "stop"  positions.  Then  rotate 
the  semaphore  shaft  backwards  and  forwards  slightly  by  hand 
while  tightening  the  bolts,  to  be  sure  that  no  binding  takes 
place  during  the  process. 

When  working  on  a  mechanism,  the  motor  door  should  always 
be  kept  closed  except  when  necessary  to  do  work  inside  of  tne 
motor. 

After  a  mechanism  has  been  wired,  the  wire  entrance  should 
be  sealed  to  prevent  the  circulation  of  air  between  the  inside 
and  outside  of  the  case.  Neglect  to  thoroughly  seal  may 
result  in  trouble  due  to  the  probable  accumulation  of  frost 
or  dirt  on  the  circuit  breaker  parts.  If  conduit  is  used  be- 
tween the  mechanism  case  and  the  pole,  the  wire  entrance 
or  conduit  should  be  likewise  sealed. 

ADJUSTMENTS 

All  signals  are  properly  adjusted  before  shipment,  the  only 
adjustments  ordinarily  required  in  the  field  being  those  due  to 
differences  in  the  semaphore  spectacles  as  follows:  if  the 
blade  is  not  horizontal  when  in  its  stop  position,  it  can  be 
brought  to  such  position  by  means  of  adjusting  screw  A  (see 
Fig.  197).  Spring  C,  adjusted  by  screw  D,  should  hold  block 
B  firmly  against  screw  A,  due  allowance  being  made  in  the 
spring  adjustment  for  any  increase  in  weight  of  the  signal 
arm,  due  to  an  accumulation  of  ice  or  sleet.  Fig.  197  shows 
relation  of  adjusting  screws,  spring,  block,  etc.,  when  used 
with  upper  quadrant  signals;  this  will  be  reversed  when  ap- 
plied to  lower  quadrant  signals. 

Having  adjusted  the  blade  to  the  horizontal  position,  the 
circuit  breaker  frame  should,  if  necessary,  be  rotated  bodily 


238 


GENERAL  RAILWAY  SIGNAL  COMPANY 


ELECTRIC   INTERLOCKING   HANDBOOK 


239 


a  sufficient  amount  to  cause  the  blade  to  assume  its  exact 
forty-five  or  ninety  degree  position  in  operation. 

Individual  adjustment  of  the  circuit  breaker  contact  springs 
should  not  be  necessary  under  ordinary  conditions.  If  required, 
great  care  should  be  exercised  to  see  that  all  contacts  are 
adjusted  to  open  and  close  as  shown  on  the  circuit  plan  which 
accompanies  each  signal  mechanism. 

In  replacing  a  circuit  breaker  which  may  have  been  removed 
from  the  mechanism  for  any  cause,  great  care  should  be  taken 
to  see  that  the  circuit  breaker  operating  segments  mesh  prop- 
erly. Otherwise,  it  will  be  impossible  for  the  blade  to  assume 


FIG.  197.     SECTION  OF  CLAMP  BEARING  SHOWING  SEMAPHORE 
SPECTACLE  ADJUSTMENT 

its  proper  positions  in  operation  except  by  extreme  adjustment 
of  the  contacts  and  circuit  breaker. 

LUBRICATION 

See  that  all  moving  parts  are  thoroughly  lubricated  with 
oil  that  will  not  thicken  in  cold  weather  or  dry  up  in  hot 
weather.  "Hydrol,"  "Polar  Ice,"  or  "3  in  One"  oils  have 
been  found  satisfactory.  Use  an  oil  can  with  a  nine  inch 
curved  spout. 

After  lubrication,  the  signals  should  be  operated  several 
times,  in  order  to  work  the  oil  thoroughly  into  the  bearings. 
The  word  "  oil "  on  the  diagram,  Fig.  196,  will  indicate  what 
parts  require  lubrication.  If  the  mechanism  has  become 
rusty,  especial  care  should  be  taken  to  see  that  all  parts 
are  operating  freely  before  attempting  to  put  the  signal  in 
service. 


240 


GENERAL  RAILWAY  SIGNAL  COMPANY 


TESTS 

If  the  signal  has  been  properly  adjusted  and  lubricated  it 
will  operate  freely.  If  in  doubt  as  to  whether  a  signal  is 
sufficiently  free  in  operation,  a  drop-away  test  should  be 
made  as  follows.  Connect  an  adjustable  resistance  in  series 
with  the  motor.  Gradually  reduce  it  until  the  motor  will  just 
move  the  blade  upwards.  Just  before  reaching  the  forty-five 
degree  position,  quickly  insert  sufficient  resistance  to  just 


APPLY  VASOJNE  TO  LOCK  DOG 
ONCE  A  YEAR 


OiL 


FIG.  198.     OILING  DIAGRAM  FOR  MODEL,  2A  DWARF  BEARING 


permit  the  motor  to  start  backwards,  moved  by  the  weight  of 
the  blade  grip.  The  current  which  will  permit  it  to  start 
backwards  from  a  given  position  should  be  approximately 
50  per  cent,  of  the  current  required  to  move  it  up  to 
that  position.  The  same  process  should  be  repeated  in  the 
ninety  degree  position  or  sixty  degree,  as  the  case  may  be. 

The  signal  having  been  oiled  and  operated  a  few  times,  see 
that  the  blade  snubs  properly  in  descending  and  also  that  the 
ratcheted  main  gear  (F,  Figs.  52  and  56)  clicks  approximately 
three  or  four  times  in  so  doing.  The  number  of  clicks  can  be 
regulated  by  the  adjusting  screw  on  the  ratcheted  main  gear. 


ELECTRIC   INTERLOCKING   HANDBOOK 


241 


MAINTENANCE 

Ordinarily  in  maintaining  a  signal,  the  only  requirements 
are  that  the  connections  be  kept  tight,  contacts  clean,  and  the 
mechanism  suitably  oiled  and  cleaned. 

Avoid  disturbing  the  commutator  or  brushes  in  any  way 
unless  found  necessary.  A  commutator  in  good  condition  will 
have  a  dark  glossy  appearance.  If,  however,  it  should  be- 
come dirty,  it  should  be  cleaned  by  chamois  skin  moistened 
with  oil,  any  surplus  oil  to  be  wiped  off  of  the  commutator  by 
a  dry  piece  of  chamois. 

Use  a  chamois  skin  in  cleaning  the  circuit  breaker  contacts. 

If  it  should  become  necessary  to  put  a  new  brush  into  a 
motor,  the  brush  should,  after  having  been  put  in  position,  be 
seated  to  the  commutator  by  drawing  thin  fine  sandpaper 
under  the  brush  while  the  brush  is  being  pressed  against  the 
commutator.  The  smooth  side  of  the  sandpaper  should  be 
against  the  commutator.  Use  "00  Single  Finishing  Flint 
Sandpaper." 


OPERATING    DATA   FOR   SIGNALS 


Operating 

Time 

Function  Operated 

Operating 
Current 

Holding 
Current 

Using 
Maximum 
Length 

Control 

Wire 

Amp. 

Amp. 

Seconds 

High  Signal,  Model  2  

3.0 

.14 

4 

High  Signal,  Model  3  or  7,   

3.0 

.11 

3 

High  Signal,  Model  2A,     

.82 

.25 

6 

Dwarf  Signal,  Model  2A,  .    .    . 

.82 

.25 

4 

Dwarf  Signal,  Model  2  or  3  

4.0 

.17 

1 

242 


GENERAL  RAILWAY  SIGNAL  COMPANY 


ELECTRIC   INTERLOCKING   HANDBOOK 


243 


Note,  OneU')mch  maximum  variation 

e«tt\«r  nay  on  total  height  of  ma  st 


Bottom  of  5'  Pipe 


-Top  Of  BrdcKet  pMt.  or  top  chord  of  Bridj*  - 


note;  Distance  betneen  center  of  pole  and  vertical  center  of  shaft  to  be 
not  le»s  than  3|  nor  more  than  4|". 

FIG.  200.    BRACKET  POST  AND  BRIDGE  SIGNAL  MASTS 
R,.  S.  A.  drawing  1037,  dated  1910. 


Mote,;  Tno (.2°)  inches  maximum  variation  aliened 
either  nay  on  total  height  of  mast. 


-not* 


Mote;  Distance  betneen  center  of  pole  and  vertical  center  of  shaft  to  be 
not  less  than  3|"nor  more  than  4|" 
FIG.  201.     GROUND  SIGNAL  MASTS 
R.  S.  A.  drawing  1035,  dated  1910. 


244 


GENERAL  RAILWAY  SIGNAL  COMPANY 


•am, 

GAUGE  or  TRACKS  is  4-9" 
WHIN  GAUSE  or  TRACKS  is  -4- 

THE  CLEARANCE  BETWEEN  SIGNAL 
AND  MAXIMUM  EQUIPMENT  LINE  WILL 
BE  i"  GREATER. 


FIG.  202.     DIAGRAM  SHOWING  CLEARANCE  BETWEEN  MODEL,  2A  DWARF 
SIGNAL  AND  THIRD  RAIL.     ELECTRIC  DIVISION, 
N.  Y.  C.  &  H.  R.  R.  R. 
Twelve  foot  track  centers. 


FIG.  203. 


METHOD  OF  TAPING  WIRES  RUNNING  FROM  MAST 
TO  SIGNAL  MECHANISM  (see  Fig.  199) 


ELECTRIC   INTERLOCKING   HANDBOOK 


245 


FIG.  204.     DIMENSIONS  OP  MODEL  2A  THREE  POSITION,  NON-AUTOMATIC 
DWARF  SIGNAL,  EQUIPPED  WITH  ELECTRIC  LAMP 


Fio.  205.     DIMENSIONS  OF  MODEL  2A  Two  POSITION,  NON-AUTOMATIC 

DWARF  SIGNAL,  EQUIPPED  WITH  OIL  LAMP 
Spectacle  R.  S.  A.  drawing  1233,  October,  1912. 


246 


GENERAL  RAILWAY  SIGNAL  COMPANY 


[  £"«.*!      }  I        I        t"r*~~  ">"["'" 


ELECTRIC   INTERLOCKING   HANDBOOK 


247 


01  Shalt 


FIG.  207.     DIMENSIONS  OF  ONE  ARM  MODEL  2  SOLENOID 

DWARF  SIGNAL 
Spectacle  R.  S.  A.  drawing  1233,  October,  1912. 


•  9j" J   T  <fc  of  shaft 

Fio.  208.     DIMENSIONS  OF  MODEL  3  SOLENOID  DWARF  SIGNAL 
Spectacle  R.  S.  A.  drawing  1233,  October,  1912. 


248 


GENERAL  RAILWAY  SIGNAL  COMPANY 


I*  S^.  Straight  Hole 


FIG.  209.     SEMAPHORE  SPECTACLE 
R.  S.  A.  Design  "A,"  drawing  1040,  October,  1912. 


FIQ.  210.     SEMAPHORE  SPECTACLE 
R.  S.  A.  Design  "B,"  drawing  1041,  October,  1912. 


ELECTRIC   INTERLOCKING   HANDBOOK 


249 


Max.  Metal  Cleat 


'*! 

-4V 

r^-ioH 

i 

r- 

.    *  j. 

^=fc  

••§' 

^f 

^•Sin 

bt 

; 

u> 

i'Bolts 

"lOlGO 

1 

r 

^ 

Taper  i: 

16 

I_ 

FIQ.  211 


*M.  Max.  Metal  Cleat 


FIG.  212 


*I4  Max.  Metal  Cleat 


Fro.  213 
BLADES  FOR  UPPER  QUADRANT  SIGNALS 

R.  S.  A.  drawing  1065,  dated  1911. 
Where  stripes  are  used  the  dimensions  shown  are  recommended. 


250 


GENERAL  RAILWAY  SIGNAL  COMPANY 


TORQUE   CURVES  FOR  R.  S.  A.  DESIGN   "A" 

SEMAPHORE   SPECTACLE 
R.  S.  A.  plan  1064.     Issue  December,  1912. 


NOTE:  FULL  LINES  wstsetrr  TORQUE  POP  SPECTACLE  MOVSMEWTS  0°  TO  90°   [STOP  TO  PROCEED] 

DOTTED  LINES  REPRESENT  TORQUE  FOR  SPECTACLE  MOVEMENTS     90°  TO  0*     fPRKEEO  TO  STOSJ 


60   -- 
55  

±  jl  

50  

45  -• 

jjjjjjjj: 

BLADE  PLATE  ,  BOLTS  AND 
•  3-6  ASH  BLADE  -  WT.  S|LBS 
.  .  ^  .         JB._  £LKT  sfMA  W|TH  2|  L9 
S,..;                   BLADE  PLATE,  BOLTS  AHO 

40  -• 
|35  ,'-2~ 

l-jjijjjj 

*  HI  II  Jamil 

-  !  b  ,  -  -  *  i,  I  I  .            2-6  ASH  BLADE  -WT.J^LO 
-  !  N  _  _  -  ,  _  x                   BtAK  PLATE  ,  BOLTS  AND 
*  -  s  '  ^  '   )0'=  SPECTACLE  COMPLETE  fcNO 

-  ^  *  4=^  "  ;        ASSUMING  BLADE  BROKEN 
"  >         OFF  AT  6RIP. 

.......  ^  EE'=  ELECT  '^MA.  wrrnouT 

-----            BLADE  ,  BLADE  PLATE 
-  -  .              OH  BOLTS  . 

I20  jjii:::::; 

15    -/-'-- 

io  j  3  ::;  •  :'  :: 

5   g<  j;  Jo.^l.u 

..!  —  -  NMINIMUM  TORQUE  LINE 
-       FOR  ELECTRIC  SEMAPHORE 
WITHOUT  BLADE  OR 
BLADE  FASTENINGS. 

/  MAXIMUM  MECHANISM 

77  1*  \  FRICTION  LINE  . 

&M&& 

0            10          20          30          40  45    50          60          70          80          90 
DECREES 

• 

h/;%$^  l- 

"" 

^Mf-Hr^R^ 

\ju^      |A 

NOTE*.  SPECTACLE  EQUIPPED  WITH   g     ROUNDELS  AND  RETAINING  MN6S  IN  ALL  CASES. 


ELECTRIC  INTERLOCKING   HANDBOOK 


251 


MOTE;    ZO"  for  Pipe  Bracket  Post. 

22"  (or  Channel  Column  Bracket  Post. 

FIG.  215.     BRACKET  POST  FOUNDATION 

R.  S.  A.  drawing  1108,  dated  1909. 

(70.3  cubic  feet  of  concrete.) 


252 


GENERAL  RAILWAY  SIGNAL  COMPANY 


Fio.  216.     GROUND  SIGNAL  MAST  FOUNDATION 

R.  S.  A.  drawing  1107,  dated  1909. 

(30.25  cubic  feet  of  concrete.) 


ELECTRIC   INTERLOCKING   HANDBOOK 


253 


J_l«16  Bolt*  Hot 


FIG.  217.     DWARF  SIGNAL  FOUNDATION  FOR  MODEL  2A, 
MODEL  3  OR  ONE  ARM  MODEL  2  DWARF  SIGNAL 
(6.5  cubic  feet  of  concrete.) 


3  3- 
•3  9"- 
-5  0"- 


i 


T- 
1 


FIG.  218.     DWARF  SIGNAL  FOUNDATION  FOR  Two  ARM 

MODEL  2  DWARF  SIGNAL 
(11.25  cubic  feet  of  concrete.) 


254 


GENERAL  RAILWAY  SIGNAL  COMPANY 


ELECTRIC   INTERLOCKING  HANDBOOK 


255 


ler 


256 


GENERAL  RAILWAY  SIGNAL  COMPANY 


^0    '(0 


ELECTRIC  INTERLOCKING   HANDBOOK 


257 


258 


GENERAL  RAILWAY  SIGNAL  COMPANY 


ELECTRIC  INTERLOCKING  HANDBOOK 


259 


260 


GENERAL  RAILWAY  SIGNAL  COMPANY 


I 

o 


en 
di 


0) 


c 

O 

O 


s 
? 


5 


ELECTRIC   INTERLOCKING   HANDBOOK 


261 


262 


GENERAL  RAILWAY  SIGNAL  COMPANY 


SECTION  X 


INSTALLATION  AND  OPERATING  DATA  FOR 
RELAYS   AND    INDICATORS 


GIVING  ENERGY  FIGURES  FOR,  AND 
DIMENSIONS  OF,  THE  D.  C.  AND  A.  C. 
RELAYS  AND  INDICATORS  USED  IN 
TRACK  AND  LINE  WORK;  ALSO  DI- 
MENSIONS OF  RELAY  BOXES 


RELAYS  AND   INDICATORS 


ENERGY   DATA   FOR  MODEL    1,  D.C.  RELAYS 


Resistance  Ohms 

Mil.  Amps. 

Volts 

4 

110 

.425 

5 

98 

.475 

9 

80 

.7 

16 

62 

1.0 

25 

52 

1.275 

30 

47 

1.4 

35 

44 

1.5 

50 

35 

1.8 

100 

26 

2.5 

300 

15.5 

4.5 

500 

13 

6.5 

800 

11 

9.0 

1000 

10.5 

10.5 

NOTE. — Values  given  in  above  table  are  the  mimimum  on  which  the 
relay  will  operate.  Add  10  per  cent,  for  practical  operation.  Drop  away 
current  equals  23  per  cent,  of  minimum  operating  current. 


ENERGY   DATA  FOR   STYLE   A,  D.C.  INDICATORS 
FOUR  WAT. 


Resistance  Ohms 

Mil.  Amps. 

Volts 

4 

147 

.59 

5 

135 

.675 

12 

97 

'  1.16 

38 

56 

2.13 

50 

49 

2.45 

75 

41 

3.10 

100 

37 

3.70 

200 

31 

6.20 

250 

27 

6.75 

500 

18 

9.00 

1000 

14 

14.00 

NOTE. —  Values  given  in  above  table  are  the  minimum  on  which  the 
indicator  will  operate.  Add  10  per  cent,  for  practical  operation.  Drop 
away  current  equals  33  per  cent,  of  minimum  operating  current. 


266 


GENERAL  RAILWAY  SIGNAL  COMPANY 


FIQ.  228.     MODEL  9,  D.C.  RELAY,  SHELF  TYPE 


FIG.  229.     MODEL  9,  D.  C.  RELAY,  WALL  TYPE 


DIMENSIONS   OF   MODEL   9   D.  C.  RELAYS 


Name 

No.  of 

Fingers 

A 

B 

C 

D 

E 

Model  9  Form  A4  Neutral  Relay,     .    .    . 

4 

6A 

7A 

9 

Model  9  Form  A6  Neutral  Relay,     .    .    . 

6 

81% 

7ft 

9 

Model  9  Form  A8  Neutral  Relay,     .    .    . 

8 

lOtf 

7A 

9 

Model  9  Form  C4  Neutral  Relay,     .    .    . 

4 

6A 

7ft 

9 

Model  9  Form  A4  Neutral  Wall  Relay,    . 

4 

61 

6ft 

8* 

5» 

ii 

Model  9  Form  A6  Neutral  Wall  Relay,    . 

6 

8 

6ft 

8* 

5| 

4i 

Model  9  Form  A4  Polarized  Relay,  .    .    . 

4 

6A 

7ft 

9 

Model  9  Form  A6  Polarized  Relay,  ..    .    . 

6 

8A 

7ft 

9 

Model  9  Form  A4  Polarized  Wall  Relay, 

4 

6J 

6ft 

8* 

5f 

4i 

Model  9  Form  A6  Polarized  Wall  Relay, 

6 

8 

6ft 

8* 

5i 

4* 

Model  9  Interlocking  Relay,  

6& 

12*i 

8 

ELECTRIC  INTERLOCKING  HANDBOOK 


267 


ENERGY  DATA  FOR 
MODEL   9,  D.  C.  RELAYS 


Resistance 
Ohms. 

4  WAY 

6  WAT 

8  WAT 

Mil. 
Amps. 

Volts 

Mil. 

Amps. 

Volts 

Mil. 

Amps. 

Volts 

3.5 

79 

.28 

95 

.34 

Ill 

.39 

4 

75 

.30 

90 

,36 

105 

.42 

4.2 

71 

.30 

85 

.36 

100 

.42 

5 

71 

.36 

85 

.43 

100 

.50 

6 

64 

.38 

76 

.46 

85 

.51 

7 

57 

.40 

69 

.49 

81 

.57 

9 

53 

.48 

64 

.58 

75 

.68 

10 

51 

.51 

61 

.61 

72 

.72 

11 

47 

.52 

56 

.62 

66 

.73 

12 

51 

.61 

61 

.73 

72 

.87 

16 

41 

.66 

49 

.79 

57 

.92 

17 

38 

.65 

46 

.79 

54 

.92 

20 

38 

.76 

46 

.93 

54 

.08 

26 

31 

.81 

37 

.97 

44 

.15 

35 

31 

1.08 

37 

1.30 

44 

.54 

40 

27 

1.08 

33 

1.32 

38 

.52 

46 

24 

1.11 

29 

1.34 

34 

.57 

50 

23 

1.15 

27 

1.35 

32 

.60 

60 

21 

1.26 

25 

1.50 

30 

.80 

68 

20 

1.36 

24 

1.64 

28 

.91 

75 

21 

1.57 

26 

1.95 

29 

2.18 

80 

20 

1.60 

25 

2.00 

29 

2.32 

90 

18 

1.62 

23 

2.07 

27 

2.43 

98 

17 

1.67 

21 

2.06 

25 

2.45 

125 

15 

1.88 

18 

2.25 

21 

2.63 

150 

14 

2.10 

16 

2.40 

19 

2.85 

200 

13 

2.60 

16 

3.20 

18 

3.60 

244 

11 

2.68 

14 

3.42 

16 

3.91 

300 

11 

3.30 

13 

3.90 

15 

4.50 

346 

10 

3.46 

12 

4.15 

14 

4.85 

400 

10 

4.00 

12 

4.80 

14 

5.60 

500 

8.5 

4.25 

10 

5.00 

12 

6.00 

516 

8.5 

4.39 

10 

5.16 

i2 

6.19 

600 

8.5 

5.10 

10 

6.00 

12 

7.20 

670 

7.5 

5.02 

9 

6.03 

11 

7.37 

800 

8 

6.40 

9.3 

7.44 

11 

8.80 

900 

7.5 

6.75 

8.5 

7.65 

10 

9.00 

1000 

7 

7.00 

8 

8.00 

9 

9.00 

1500 

6 

9.00 

7 

10.5 

8 

12.00 

1600 

5.5 

8.80 

6.5 

10.40 

7.5 

12.00 

NOTE. — Values  given  in 
will  operate.  Add  10  per 
rent  equals  40  per  cent,  of 


above  table  are  the  minimum  on  which  the  ielay 
cent,  for  practical  operation.  Drop  away  cur- 
minimum  operating  current, 


268 


GENERAL  RAILWAY  SIGNAL  COMPANY 


Fia.  230.     MODEL  9,  D.  C.  INDICATORS 


FIG.  231.    THREE  POSITION  D.  C.  MOTOR  RELAY 

This  relay  requires  the  same  amount  of  energy  for  operation  as  the 
Model  9,  D.  C.  Relay.  Drop  away  current  equals  50  per  cent,  of  normal 
operating  current. 


ELECTRIC   INTERLOCKING  HANDBOOK 


269 


ENERGY   DATA    FOR 
MODEL   9,  D.  C.  INDICATORS 


Resis. 

TOWER  INDICATORS 

SWITCH 
INDICATOR 

4  Way 

6  Way 

8  Way 

Ohms 

Mil. 
Amps. 

Volts 

Mil. 
Amps. 

Volts 

MIL 

Amps, 

Volts 

Mil. 
Amps. 

Volts 

4 

101 

.40 

107 

.43 

113 

.45 

101 

.40 

4.4 

94 

.42 

100 

.44 

106 

.47 

94 

.42 

6.8 

75 

.51 

79 

.54 

83 

.56 

75 

.51 

9 

66 

.60 

70 

.63 

74 

.66 

66 

.60 

9.2 

65 

.60 

69 

.63 

73 

.67 

65 

.60 

14 

55 

.77 

58 

.82 

61 

.85 

55 

.77 

20 

45 

.90 

48 

.97 

51 

1.02 

45 

.90 

22 

44 

.96 

47 

1.03 

50 

1.10 

44 

.96 

30 

37 

1.11 

39 

1.18 

41 

1.23 

37 

1.11 

34 

35 

1.19 

37 

1.26 

39 

1.33 

35 

1.19 

40 

30 

1.20 

32 

1.28 

34 

1.36 

30 

1.20 

50 

29 

1.45 

31 

1.55 

33 

1.65 

29 

1.45 

56 

27 

1.51 

29 

1.62 

31 

1.73 

£7 

1.51 

92 

24 

2.20 

26 

2.39 

28 

2.57 

24 

2.20 

100 

22 

2.20 

23 

2.30 

25 

2.50 

22 

2.20 

130 

19 

2.47 

20 

2.60 

21 

2.73 

19 

2.47 

200 

15 

3.00 

16 

3.20 

17 

3.40 

15 

3.00 

300 

13 

3.90 

14 

4.20 

15 

4.50 

13 

3.90 

500 

11 

5.50 

12 

6.00 

13 

6.50 

11     . 

5.50 

690 

8.5 

5.86 

9 

6.21 

9.5 

6.55 

8.5 

5.86 

1000 

7.5 

7.50 

8 

8.00 

8.5 

8.50 

7.5 

7.50 

NOTE. — Values  given  in  above  table  are  the  minimum  on  which  the 
indicator  will  operate.  Add  10  per  cent,  for  practical  operation.  Drop 
away  current  equals  33  per  cent,  of  minimum  operating  current. 


270 


GENERAL  RAILWAY  SIGNAL  COMPANY 


t^£Nij 

7'/8- 


FIG.  232.     RELAY— WALL  OR  SHELF  TYPE 


f  ~ 


FIG.  233.     TOWER  INDICATOR 


4f- 


FIG.  234.  INDICATING  RELAY 

MODEL  2  FORM  B,  MODEL  3  FORM  B,  OR  MODEL  Z  FORM  B,  A.  C. 
RELAYS  AND  INDICATORS 


ELECTRIC   INTERLOCKING  HANDBOOK 


271 


ENERGY   DATA   FOR   A.  C.  LINE   RELAYS   AND    INDICATORS 
FOB  USE  ON  55-110  OR  220  VOLTS,  —  25  OR  60  CYCLES. 


MAXIMUM  ENERGY  REQUIRED  AT  NORMAL 

VOLTAGE  (SEE  NOTE) 

Name  of  Device 

Cycles 

2  Position 

3  Position 

Split  Phase 

Local 

Line 

V.  A. 

Watts 

V.  A. 

Watts 

V.  A. 

Watts 

Model  2  Form  A  Line  ] 

Relays,  with  6  front, 

6  back  or  12  front  con- 

25 

12.0 

10.0 

7.8 

5.4 

6.4 

5.4 

tacts,  and  indicating 

60 

12.0 

10.0 

7.8 

5.4 

6.4 

5.4 

attachment  for  tower 

use,  

Model  2  Form  B  Line  ] 

Relays,  with  6  front, 
2  back  contacts,  and  ^ 
indicating   attach- 

25 
60 

15.0 
15.0 

10.0 
10.0 

11.7 
11.7 

5.4 
5.4 

6.5 
6.5 

% 
5.4 
5.4 

ment  for  tower  use,  .  J 

Model  Z  Form  B   Line  ] 

Relays,  with  6  front, 
2  back  contacts,  and  ^ 
indicating  attach- 

25 
60 

5.5 
10.0 

2.0 
3.0 

ment  for  tower  use,  .  j 

Model  2  Form  B  Switch  | 
Indicator,    without  > 
contacts,      ) 

25 
60 

15.0 
15.0 

10.0 
10.0 

... 

Model  Z  Form  B  Switch 
Indicator,    without  >- 

25 
60 

3.0 
5.5 

1.5 

1.8 

contacts,      ) 

Model  2  Form  B  Tower 
Indicator,    without  V 
contacts                        .   j 

25 
60 

15.0 
15.0 

10.0 
10.0 

Model  Z  Form  B  Tower 
Indicator,    without  > 

25 
AH 

3.0 

5C 

15 

10 

contacts,     ) 

OU 

.  D 

.  .  o 

NOTE.  —  Above  energy  figures  will  permit  practical  operation  of  these  de- 
vices on  a  voltage  20  per  cent,  below  normal  and  are  based  on  a  maximum 

equipment    of    contacts,    including    indicating    attachment    for  tower  use. 
Without  indicating  attachment,  with  a  lesser  number  of  contacts,  by  spe- 


cial construction,  or  by  combinations  of  any  of  the  foregoing,  the  above 

energy  may  be  reduced  20  to  50  per  cent.  Re" 

less  than  50  per  cent,  of  the  minimum  operating  energy. 


may  be  reduced  20  to  50  per  cent.  Relay  must  drop  away  on  not 


NOTE. —  The  above  table  permits  the  following  line  resistance  in  series 
with  line  phase  of  relay. 


Volts 

Cycles 

Resistance  (Ohms) 

55 

25 

75 

55 

60 

100 

110 

25 

150 

110 

60 

200 

220 

25 

250 

220 

60 

300 

272 


GENERAL  RAILWAY  SIGNAL  COMPANY 


8^8- 4  Nay 


FIG.  235.     MODEL  2  FORM  A 
POLYPHASE  RELAT 


FIG.  236.     MODEL  2  FORM  A 

POLYPHASE  INDICATING 

RELAY 


FIG.  237. 


SIDE  VIEW  OF  MODEL  2  FORM  A  POLYPHASE 
RELAY  OR  INDICATING  RELAY 


ELECTRIC   INTERLOCKING   HANDBOOK 


273 


OPERATION    OF   THE    MODEL   2   FORM    A    REGULAR   POLY- 
PHASE  RELAY,  IN  CONNECTION  WITH   DOUBLE   RAIL 
A.  C.  TRACK    CIRCUITS   ON   ELECTRIFIED 
DIRECT  CURRENT   ROADS 


POHtR  LIME 


TwwvJ 

nG* 


TRAHSrORMER 
VOLT  AMPERES  TOR  CURVES  MEASURED  AT  THESE   POIMT5 

MODEL  Z  FORM  A  RELAY 
IMPEDANCE  BOND  IMPEDANCE 


FIG.  238.     END  FED  DOUBLE  RAIL  A.  C.  TRACK  CIRCUIT 

VOLT-AMPERES 


too 


)  1000        ZOOO        3000        4000       5000        6000        7000         8000        9000 

LENGTH  OF  TRACK  CIRCUIT  IN  FEET 

FIG.  239.     CURVE  SHOWING  ENERGY  REQUIRED  FOR 
OPERATION  ON  25  CYCLE  CURRENT 


VOLT-AM  PE 
150 

1?5 
100 
75 
50 
25 
n 

RES 

I 

\    \ 

/ 

/ 

AVER0 

GE  BALLAST^ 

k/ 

/ 

L>^|         # 

^ 

^ 

^ 

•M 

*=i 

•**• 

^ss 

e= 

•Z— 

*-~~* 

^GOOD  BALLAST 

TTT 

0  1000        ZOOO         3000       4000         5000        6000       7000        8000       9000 

LENGTH  OF  TRACK  CIRCUIT  IN  FEET 

FIG.  240.     CURVE  SHOWING  ENERGY  REQUIRED  FOR 
OPERATION  ON  60  CYCLE  CURRENT 

NOTE. — Volt  amperes  shown  in  Figs.  239  and  240  are  the  total  of  the  volt 
amperes  fed  to  the  track  circuit  and  to  the  relay  local.  Relay  is  equipped 
with  four  front  and  two  back  contacts.  Curves  are  based  on  85  pound 
rail  being  used. 

Good  ballast  (approximately  10  ohms  per  1,000  ft.)  consists  of  rock  or 
gravel  ballast,  well  drained  and  free  from  the  base  of  the  rails. 

Average  ballast  (approximately  5  ohms  per  1,000  ft.)  consists  of  a  ballast, 
such  as  a  well  drained  gravel  ballast,  covering  the  base  of  the  rails. 

Dirt,  cinder  or  badly  drained  gravel  ballast,  covering  the  base  of  the  rails, 
is  considered  poor  and  necessitates  the  use  of  much  more  energy  for  the 
operation  of  track  circuits  than  is  shown  in  the  curves. 


274 


GENERAL  RAILWAY  SIGNAL  COMPANY 


TABLE    SHOWING   RELATIVE   AMOUNT   OF   ENERGY   RE- 
QUIRED  FOR   MODEL   2   FORM   A   TRACK   RELAYS, 
REGULAR  AND  QUICK  ACTING,  WITH  DIF- 
FERENT  CONTACT   COMBINATIONS 


Model  2  Form  A 
Track  Relays 

Contact  Equipment 

Relative  Amount 
of  Energy 
Required 

Regular  

4  front,  2  back, 

1  0 

Regular,    

2  front,  2  back,   .    .    . 

8 

Regular,    
Quick  Acting,  

6  front,  2  back,   
2  front,  2  back,   .    .    . 

1.4 
3  5 

Quick  Acting  
Quick  Acting,  

4  front,  2  back,   
6  front,  2  back,    

3.5 
4.2 

NOTE. — Regular  Model  2  Form  A  relay  with  four  front  and  two  back 
contacts  taken  as  unity.  For  energy  required  by  this  relay  on  25  or  60 
cycle  operation,  see  curves  on  page  273. 


MS0 


\Z' 


FIG.  241. 


WOOD  RELAY  Box  FOB  MODEL  2  FOEM  A 
POLYPHASE  RELAYS 


ELECTRIC   INTERLOCKING   HANDBOOK 


275 


FIG.  242. 


IRON  RELAY  Box  FOR  D.  C.  RELAYS  AND 
FORM  B,  A.  C.  RELAYS 


Fia,  243.     WOOD  RELAY  Box  FOR  D.  C.  RELAYS  AND 
FORM  B,  A.  C.  RELAYS 


276 


GENERAL  RAILWAY  SIGNAL  COMPANY 


UMPCRE 


tr 


RESISTANCE  100  OHMS 


Pro.  244.    CIRCUIT  FOR  TESTING  PICK  UP  AND  DROP  AWAY  OF 
D.  C.  TRACK  RELAYS 


RtMSTANCt    100  OHV*» 


•E  VOLTS 

T 


FIG.  245. 


CIRCUIT  FOR  TESTING  PICK  UP  AND  DROP  AWAY  OF 
D.  C.  LINE  RELAYS 


1  JkMPtRE.  RANGE. 


FIG.  246.     CIRCUIT  FOR  TESTING  RESISTANCE  OF  RELAY  CONTACTS 
(Resistance  equals  voltage  divided  by  current.) 


NOTE. —  Several  readings  should  be  made  in  above  tests  and  the  average 
taken. 

The  resistance  used  in  Figs.  244  and  245  consists  of  a  resistance  with  a 
variable  center  connection.  It  should,  preferably,  have  uniformly  graduated 
steps.  The  resistance  used  in  Fig.  246  may  merely  be  a  unit  of  such 
resistance  as  to  protect  the  instrument.  It  is  recommended,  however, 
that  a  variable  resistance  be  used  if  available.  If  voltages  used  in  above 
tests  are  higher  than  those  indicated,  the  resistances  used  will  have  to  be 
increased  accordingly. 

The  ammeter  for  all  of  the  above  tests  should  not  have  a  range  greatly 
exceeding  the  1  ampere  range  indicated  above. 


SECTION  XI 


INSTALLATION  AND  OPERATING  DATA  FOR 
TRANSFORMERS 


COVERING   DIMENSIONS   AND   RATINGS 
OF  LINE  AND  TRACK  TRANSFORMERS 


TRANSFORMERS 


FIG.  247 
DIMENSIONS   OF   TYPE    L   LINE   TRANSFORMERS 


DIMENSIONS  (APPROXIMATE) 

Size 

A 

B 

C 

D 

E 

F 

Q 

H 

Inch 

Inch 

Inch 

Inch 

Inch 

Inch 

Inch 

Inch 

1 

13™Ao 

12% 

10 

11 

7% 

8% 

2%e 

8 

2 

15H 

13% 

1  l18Ae 

1218/16 

8% 

10 

3%o 

8 

3 

17 

15H 

13% 

14% 

10 

11% 

4%6 

8 

FIQ.  248.     HANOBR  IKONS 


280 


GENERAL  RAILWAY  SIGNAL  COMPANY 


STANDARD  RATINGS   OF   G.  R.  S.  TYPE    L   TRANSFORMERS 

SIN  OLE  PHASE,  OIL  IMMERSED,  SELF  COOLED,  POLE  TYPE 

Primary  voltage,  2200  —  25  cycles. 


TOTAL 
CAPACITY 

SECONDARY  LINE  WINDINGS 

SECONDARY  TRACK  WINDINGS 

Size 

V.  A. 

No.  of 
Wind- 
Ings 

V.  A. 
Each 

Volts 

Taps 
See  Note 

No.  of 
Wind- 
ings 

V.  A. 

Each 

Volts 

Taps 
See  Note 

1 

200 

1 

200 

110-220 
or 
55-110 

As  Req'd 

None 

1 

200 

None 

... 

.... 

(1 

200 

10 

2  &  6  V,  or 
aa  Req'd 

1 

400 

1 

400 

110-220 
or 
55-110 

As  Req'd 

None 

1 

400 

1 

200 

110-220 
or 
55-110 

As  Req'd 

1 

200 

10 

2  &  6  V,  or 
aa  Req'd 

1 

400 

None 

2 

200 

10 

2  &  6  V,  or 
as  Req'd 

2 

600 

1 

600 

110-220 
or 
55-110 

As  Req'd 

None 

2 

600 

1 

400 

110-220 
or 
55-110 

As  Req'd 

1 

200 

10 

2  &  6  V,  or 
as  Req'd 

2 

600 

1 

200 

110-220 
or 
55-110 

As  Req'd 

2 

200 

10 

2  &  6  V,  or 
as  Req'd 

3 

1000 

1 

1000 

110-220 
or 
55-110 

As  Req'd 

None 

3 

1000 

1 

800 

110-220 
or 
55-110 

As  Req'd 

1 

200 

10 

2  &  6  V,  or 
as  Req'd 

3 

1000 

1 

600 

110-220 
or 
55-110 

As  Req'd 

2 

200 

10 

2  &  6  V,  or 
as  Req'd 

NOTE. —  Terminal  board  is  arranged  to  take  three  windings,  each  to 
have  five  terminal  posts,  which  provides  for  a  maximum  of  three  taps 
per  winding.  If  less  than  three  windings  are  used,  it  will  be  seen  that 
additional  posts  will  be  available  for  taps  if  same  are  desired. 


ELECTRIC   INTERLOCKING   HANDBOOK 


281 


STANDARD   RATINGS   OF   G.  R.  S.  TYPE   L   TRANSFORMERS 

SINGLE  PHASE,  OIL  IMMERSED,  SELF  COOLED,  POLE  TYPE 

Primary  voltage,  2200  —  60  cycles. 


TOTAL 
CAPACITY 

SECONDARY  LINE  WINDINGS 

SECONDARY  TRACK  WINDINGS 

Size 

V.  A. 

No.  of 
Wind- 
ings 

V.  A. 
Each 

Volts 

Taps 
See  Note  1 

No.  of 
Wind- 
ings 

V.  A. 
Each 

Volts 

Taps 
See  Note  1 

1 

200 

1 

200 

110-220 
or 
55-110 

As  Req'd 

None 

1 

200 

None 

1 

200 

10 

2  &  6  V,  or 
as  Req'd 

1 

400 

1 

400 

110-220 
or 
55-110 

As  Req'd 

None 

1 

400 

1 

200 

110-220 
or 
55-110 

As  Req'd 

1 

200 

10 

2  A  6  V,  or 

as  Req'd 

1 

400 

None 

....." 

2 

200 

10 

2  &  6  V,  or 
as  Req'd 

1 

600 

1 

600 

110-220 
or 
55-110 

As  Req'd 

None 

1 

600 

1 

400 

110-220 
or 
55-110 

As  Req'd 

1 

200 

10 

2  &  6  V.  or 
as  Req'd 

1 
2 

600 

1 

200 

110-220 
or 
55-110 

As  Req'd 

2 

200 

10 

2  &  6  V,  or 
as  Req'd 

1000 

1 

1000 

110-220 
or 
55-110 

As  Req'd 

None 

2 

1000 

1 

800 

110-220 
or 
55-110 

As  Req'd 

1 

200 

10 

2  &  6  V,  or 
as  Req'd 

2 

1000 

1 

600 

110-220 
or 
55-110 

As  Req'd 

2 

200 

10 

2  &  6  V,  or 
as  Req'd 

3 

3000 

1 

3000 

110-220 
or 
55-110 

As  Req'd 

None 

See 
Note 
2 



NOTE  1. —  Terminal  board  is  arranged  to  take  three  windings,  each  to 
have  five  terminal  posts,  which  provides  for  a  maximum  of  three  taps  per 
winding.  If  less  than  three  windings  are  used,  it  will  be  seen  that  addi- 
tional posts  will  be  available  for  taps  if  same  are  desired. 

NpTE  2. — Track  secondary  windings  can  be  placed  on  the  3,000  V.  A. 
eize  if  desired. 


282 


GENERAL  RAILWAY  SIGNAL  COMPANY 


FIG.  249.     TYPE  K  SECONDARY  TRACK  TRANSFORMER 


STANDARD    RATINGS   OF   G.  R.  S.  TYPE   K   TRANSFORMERS 
SINGLE  PHASE,  AIR  COOLED 


25  Cycles 

GO  Cycles 

50  V.  A. 
100  V.  A. 
200  V.  A. 

50  V.  A. 
100  V.  A. 
200  V.  A. 

The  above  ratings  are  for  110  volt  primary.  Ten  or  twenty  volts  sec- 
ondaries can  be  furnished,  equipped  with  a  maximum  of  six  taps  when 
required. 


R.  S.  A.  VOLTAGE   RANGES  FOR   SIGNAL  WORK 

(1913) 

(1st  Range)  Thirty  (30)  and  less. 

(2d  Range)  Over  thirty  (30)  to  and  including  one  hundred 
and  seventy-five  (175). 

(3rd  Range)  Over  one  hundred  and  seventy-five  (175)  to  and 
including  two  hundred  and  fifty  (250). 

(4th  Range)  Over  two  hundred  and  fifty  (250)  to  and  in- 
cluding six  hundred  and  sixty  (660). 

(5th  Range)  Over  six  hundred  and  sixty  (660). 


SECTION   XII 


INSTALLATION  AND  OPERATING  DATA  FOR 
PRIMARY   BATTERIES 


COVERING     THE     CAUbTIC     SODA 

CELL,    GRAVITY    CELL    AND    DRY 

CELL 


PRIMARY   BATTERIES 


CAUSTIC   SODA   PRIMARY  CELL 

USES 

THE  caustic  soda  primary  battery  is  largely  used  on  open 
circuit  work,  such  as  for  signal  operation,  where  a  higner 
current  is  required  than  can  be  secured  from  other  types 
of  primary  batteries  without  the  installation  of  a  great  num- 
ber of  cells.  A  somewhat  different  design  of  caustic  soda  cell 
is  extensively  used  for  track  circuit  work;  although  a  more 
expensive  cell  than  the  gravity  cell,  it  is  one  in  which  the 
maintenance  is  very  slight,  it  being  ordinarily  necessary  to 
make  renewals  only  four  or  five  times  a  year,  this,  of 
course,  depending  on  the  type  of  traffic  passing  over  the 
section  on  which  the  battery  is  installed. 

DESCRIPTION 

The  elements  of  the  cell  are  of  zinc  and  black  oxide  of 
copper  and  the  electrolyte  a  strong  solution  of  caustic  soda 
and  water.  These  are  generally  contained  in  a  porcelain  or 
heavy  heat  resisting  glass  jar,  the  latter  being  preferable  due 
to  its  freedom  from  breakage  and  the  ease  with  which  inspec- 
tion is  made.  The  cut  on  page  286  gives  the  appearance  of 
the  jar  adopted  by  the  R.  S.  A.  as  their  standard,  the  ampere 
hour  capacity  of  this  standard  cell  being  400. 

The  elements  of  the  signal  cell  are  generally  cast  in  the 
form  of  plates  which  are  suspended  from  the  cover.  This 
cell  has  an  extremely  low  internal  resistance  (about  .045  ohm) 
and  is  hence  capable  of  producing  on  short  circuit  the  heavy 
current  of  20  amperes.  The  E.  M.  F.  of  the  cell  is  low;  when 
new,  it  is  approximately  0.7  volt  and  this  falls  off  after  the  cell 
has  been  in  service  for  some  time. 

The  elements  used  in  the  track  cell  are  not  necessarily  of 
the  same  type  as  those  used  in  the  signal  cell.  One  well-known 
cell  used  for  track  circuit  work  has  a  zinc  element  similar  in 
form  to  the  zinc  in  the  gravity  cell,  the  other  element  being 
poured  loose  over  a  tin  disc  resting  on  the  bottpm  of  the  jar. 
The  track  cell  is  designed  to  have  an  internal  resistance  of 
about  0.25  ohm  and  a  current  output  on  short  circuit  of  about 
2  to  3  amperes.  The  voltage  of  the  cell  is  the  same  as  that  of 
the  signal  cell. 

ACTION  OF  THE  CELL 

When  in  service,  chemical  action  of  the  cell  gradually  dis- 
solves the  zinc  element  and  converts  the  copper  oxide  into 
pure  copper.  In  the  case  of  the  signal  cell  using  a  copper 
oxide  plate,  this  change  in  the  element  will  consist  of  the 
reduction  of  the  copper  oxide  to  copper,  this  reduction  taking 
place  from  the  surface  and  extending  inward;  the  relative 


286 


GENERAL  RAILWAY   SIGNAL  COMPANY 


R.  S.  A.  SIGNAL   CELL 

CAUSTIC  SODA  PRIMARY  BATTERY 

R.  S.  A.  plan  1053.     Issue  October,  1912. 

(Revision  of  plan  1053.     Issue,  1911.) 


BARREL     SHAPE 

HEAT  RESISTING 
GLASS  JAR 


NOTES 

THE  ASSEMBLED  ELEMENT  shall  be 
BO  arranged  that  when  attached  to  the 
cover  and  the  nut  on  the  upper  side 
tightened  to  place,  the  element  will  be 
at  the  proper  height  in  the  solution. 

Terminal  wire  shall  be  No.  12  B  &  S 
gauge  solid  soft  drawn  copper  wire 
covered  with  an  insulation  suitable  to 
withstand  the  action  ol  the  oil  and 
electrolyte.  Insulation  on  end  of 
wire  shall  be  trimmed  either  tapered 
or  square  and  in  this  operation  the 
wire  must  not  be  scored. 

Suspension  bolt  shall  be  iron,  cop- 
per plated. 

JAR  AND  COVER  shall  conform  to 
the  dimensions  shown,  with  reason- 
able allowance  for  slight  irregularities 
In  manufacture. 

Top  of  jar  shall  be  square  with 
vertical  axis  and  cover  shall  be  per- 
fectly flat. 

Manufacturer's  name  or  trade 
marl?  shall  be  shown  on  cover. 

Porcelain  jars  shall  be  glazed  inside 
and  out  and  covers  on  top  and  edge. 

A  solution  line  consisting  of  a  slight 
ridge  or  depression  extending  around 
the  inside  of  porcelain  jars  and  the 
outside  of  glass  jars  shall  be  placed 
as  shown. 


ELECTRIC   INTERLOCKING   HANDBOOK  287 


degree  of  exhaustion  of  the  cell  can  be  ascertained  by- 
scraping  off  the  material  from  the  outside  of  the  plate  until 
the  dark  copper  oxide  is  exposed.  In  the  cell  used  for  track 
circuit  work,  the  copper  oxide  is  converted  into  copper  flakes 
which  continue  to  lie  as  before  on  the  tin  disc  in  the  bottom 
of  the  jar. 

CARE  OF  THE  CELL 

In  setting  up  the  cell,  the  jar  should  be  first  thoroughly 
cleaned  and  then  filled  with  pure  water  (preferably  clear  rain 
water)  to  such  a  height  that  when  the  elements  are  added  the 
level  of  the  electrolyte  will  have  been  raised  to  within  about 
one  and  one-half  inches  of  the  top  of  the  jar.  The  soda 
should  be  added  slowly  and  the  solution  stirred  continuously 
with  a  stick  until  the  soda  is  entirely  dissolved.  Chemical 
changes  raise  the  temperature  of  the  solution  to  the  boiling 
point,  making  it  necessary  to  place  ordinary  glass,  or  porcelain 
jars,  on  a  dry  wood  surface  when  mixing  the  solution,  to  pre- 
vent breakage  of  the  jars.  The  elements  should  not  be  placed 
in  the  cells  until  the  temperature  of  the  solution  has  dropped 
to  about  90  degrees  Fahr.  A  thin  film  of  oil  should  then  be 
poured  over  the  top  of  the  electrolyte  to  prevent  evaporation 
and  "creeping  of  the  salts." 

When  mixing  the  solution,  care  should  be  taken  not  to  get 
the  caustic  soda  dust  or  solution  on  one's  person,  as  it  is  very 
corrosive ;  the  best  means  for  counteracting  the  action  of  caus- 
tic soda  is  water  or  oil. 

When  in  service  practically  no  other  attention  is  required 
by  the  cell  other  than  an  occasional  inspection  of  the  elements 
to  determine  the  degree  of  exhaustion  of  the  cell. 

The  caustic  soda  solution  does  not  freeze,  but  when  subjected 
to  severe  cold  the  current  discharge  of  the  battery  is  mate- 
rially reduced,  which  makes  it  advisable  to  furnish  protection 
against  extreme  temperature  conditions  where  current  for 
operating  signal  motors  is  required,  or  if  an  equivalent  current 
is  wanted  for  any  other  purpose. 


EXTRACT   FROM   R.  S.  A.  SPECIFICATIONS  ]  FOR 
CAUSTIC   SODA  PRIMARY  CELL  (1911) 

1.  GENERAL 

This  battery  is  to  be  used  in  the  operation  of  signals, 
crossing  alarms,  etc. 

2.  MATERIAL 

(a)  Railway  Signal  Association  drawing  1053,  issue 
1911,  shows  tne  general  design  and  dimensions  of  the  bat- 
tery jar,  coyer,  connections,  wire,  and  that  part  of  the  bolt, 
together  with  nuts  and  washers,  shown  above  the  cover 
for  supporting  the  elements.  The  active  part  of  the  cell 


288  GENERAL  RAILWAY  SIGNAL  COMPANY 


consists  of  the  zinc,  copper  oxide,  and  caustic  soda  in  the 
granular  form,  which,  mixed  with  water,  forms  the  solu- 
tion in  which  the  elements  are  placed,  and  a  suitable 
mineral  oil,  which  is  used  on  top  of  the  caustic  soda  solu- 
tion to  prevent  evaporation  and  the  salts  from  creeping 
over  the  top  of  the  jar. 

(6)  The  assembled  element  shall  consist  of  the  zinc  and 
copper  oxide,  suitably  combined,  together  with  the  suspen- 
sion bolt  and  terminal  wire  of  sufficient  length  to  extend 
twelve  (12)  inches  above  top  of  cover. 

3.  REQUIREMENTS 

Each  complete  cell  or  renewal  shall  have  a  capacity  of 
at  least  four  hundred  (400)  ampere  hours,  as  provided  for 
under  test  in  Section  4. 

4.  TEST 

(a)  In  order  to  determine  the  ampere  hour  capacity  of 
the  cell  or  renewal,  one  will  be  selected  at  random  from 
each  lot  of  one  hundred  (100),  or  fraction  thereof,  and 
placed  on  a  continuous  discharge  of  one  (1)  ampere.  If 
the  discharge  continues  four  hundred  (400)  hours  without 
the  potential  at  the  terminals  of  the  cell  dropping  below 
five-tenths  (0.5)  of  one  (1)  volt  per  cell,  the  cell  or  renewal 
will  be  considered  acceptable  as  far  as  capacity  is  concerned. 

(6)  One  will  be  selected  at  random  from  each  lot  of  one 
hundred  (100),  or  fraction  thereof,  and  subjected  to  a  dis- 
charge of  three  (3)  amperes  continuously.  If,  during  the 
first  forty  (40)  hours,  the  voltage  does  not  drop  below 
fifty-three  hundredths  (0.53)  of  one  (1)  volt  and  during  the 
next  forty  (40)  hours  the  voltage  does  not  drop  below 
five-tenths  (0.5)  of  one  (1)  volt,  the  cell  or  renewal  will  be 
considered  acceptable  so  far  as  drop  in  voltage  test  is 
concerned. 

(c)  Tests  enumerated  in  paragraphs  (a)  and  (b)  will  be 
made  at  a  temperature  of  seventy  (70)  degrees  Fahr. 


THE   GRAVITY   CELL 
USES 

The  primary  cell  in  most  general  use  on  low  voltage  closed 
circuit  work  is  the  gravity  cell ;  it  is  extensively  used  in  con- 
nection with  track  circuits,  being  adapted  to  this  type  of  work 
by  its  constant  voltage  characteristics  and  its  freedom  from 
polarization  when  on  closed  circuit.  Although  frequently 
used  on  open  circuit  work,  it  is  not  recommended  that  the 
cell  be  used  that  way,  due  to  the  very  low  efficiency  obtained 
when  operating  under  those  conditions. 


ELECTRIC   INTERLOCKING   HANDBOOK  289 


DESCRIPTION 

The  elements  of  this  cell  are  of  zinc  and  copper,  and  the 
electrolyte  a  solution  formed  by  dissolving  copper  sulphate 
or  "Blue-stone"  in  pure  water.  The  electrolyte  and  elements 
are  contained  in  a  glass  jar  about  eight  inches  in  height  and 
six  inches  in  diameter. 

In  the  type  of  cell  generally  employed  for  signal  purposes, 
the  zinc  element  consists  of  about  four  pounds  of  metallic 
zinc,  cast  in  the  shape  of  a  ring,  which  is  suspended  from  the 
upper  edge  of  the  glass  jar  by  means  of  soft  wire  hangers  cast 
into  the  element.  The  copper  element,  made  of  thin  sheet 
copper,  rests  on  the  bottom  of  the  jar  and  is  covered  with 
copper  sulphate  crystals. 

The  gravity  cell  has  an  approximately  constant  E.  M.  F. 
of  1  volt  on  open  circuit  and  does  not  polarize  through  being 
continually  short  circuited.  The  internal  resistance  varies 
considerably  with  the  condition  of  the  cell,  running  from 
about  an  ohm  when  the  cell  is  in  good  condition  to  as 
high  as  2  or  3  ohms.  When  in  the  best  condition  the  cell 
has  a  current  capacity  on  short  circuit  of  about  1  ampere. 

ACTION  OF  THE  CELL 

When  first  set  up,  if  there  are  no  old  cells  from  which  to 
get  zinc  sulphate  to  use  in  new  cells,  the  battery  must  be  short 
circuited  from  twenty-four  to  forty-eight  hours  in  order  to 
start  the  action  of  the  cell  and  to  reduce  the  internal  resist- 
ance. A  saturated  solution  of  copper  sulphate  soon  forms 
around  the  copper  element,  and  after  the  cell  has  been  on  short 
circuit  for  a  number  of  hours,  a  zinc  sulphate  is  formed  around 
the  zinc.  Due  to  the  difference  of  the  specific  gravities  of 
these  two  sulphates,  the  zinc  sulphate  floats  on  the  copper 
sulphate,  this  giving  to  the  cell  the  name  of  "  gravity  cell." 

The  action  of  the  cell  causes  the  copper  sulphate  crystals  to 
dissolve,  and  when  the  cell  is  producing  current  a  deposit  of 
pure  copper  is  made  on  the  copper  element.  The  zinc  of  the 
other  element  is  consumed,  its  surface  soon  becoming  covered 
with  a  deposit  of  grey  and  brown  sludge.  This  residue  consists 
of  part  of  the  impurities  of  the  zinc,  which  does  not  dissolve,  and 
if  not  scraped  off  at  about  intervals  of  two  weeks  it  will  coat 
the  zinc  to  such  an  extent  as  to  interfere  with  the  action  of 
the  cell.  As  the  cell  wears  out  the  zinc  sulphate  increases 
and  the  copper  sulphate  decreases;  the  copper  sulphate 
crystals  in  the  bottom  of  the  cell  are  reduced  to  a  paste,  and, 
as  mentioned  before,  the  zinc  element  becomes  eaten  away 
by  the  chemical  action.  The  degree  of  exhaustion  of  the  cell 
can  be  determined  by  the  condition  of  the  zinc  element  and 
the  amount  of  copper  sulphate  crystals  remaining  in  the 
bottom  of  the  jar. 


290 


GENERAL  RAILWAY  SIGNAL  COMPANY 


R.  S.  A.  ZINC 
GRAVITY  PRIMARY  BATTERY 
R.  S.  A.  plan  1087.     Issue  October,  1911. 

SPECIFICATION 

1.  Zincs  shall  be  made  from  virgin  spelter 
cast  at  a  low  temperature  and  shall  be  thor- 
oughly 'amalgamated  with  mercury.  They 
shall  be  uniform  in  size  and  weight,  free  from 
flaws  and  mechanical  defects  and  shall  have  a 
smooth  outer  surface.  A  fracture  of  the  zinc 
must  show  the  grain  firm  and  close. 

2  The  size  and  shape  of  zincs  shall  conform 
closely  to  this  drawing. 

The  brass  binding  post  roust  be  firmly  con- 
nected both  mechanically  and  electrically  to 
the  zinc.  The  thumb  screw  must  be  perfectly 
threaded  and  must  fit  closely 

The  manufacturer's  name  must  be  cast  on 
the  upper  flat  surface  of  the  zinc  in  as  large 
letters  as  the  surface  will  permit  and  must  be 
raised  not  less  than  three-thirty-seconds  (&> 
inch  above  the  surface  In  addition,  the  manu- 
facturer's name  or  trade-mark  must  be  stamped 
on  some  other  part  in  such  a  position  as  not  to 
be  effaced  by  the  action  of  the  electrolyte  or 
by  the  process  of  cleaning. 

3  Weight.    The  zincs  shall  weigh  four  (4) 
pounds  each 

4.  The  chemical  composition  of  the  finished 
zincs  shall  be  as  follows: 

Mercury  not  less    than    2  00% 

Iron  not  more  than       10% 

Lead  not  more  than       50% 

Other  impurities  not  more  than       40% 
Zinc  not  less    than  97  00% 

5.  When  a  shipment  of  zincs  is  received,  an 
examination   will   be  made  to  see  that  the 
physical  requirements  are  fulfilled,  and  >f  found 
satisfactory,  one  zinc  from  each  fifty  (50)  or 
fraction  thereof  will   be  taken  for  chemical 
analysis.     The  results  of  this  analysis  shall  de- 
termine whether  the  shipment  will  be  accepted. 

In  the  event  of  controversy  with  the  manu- 
facturer over  the  chemical  composition,  one  zmc 
from  each  50  or  fraction  thereof  shall  be  sub- 
mitted to  a  disinterested  chemist,  acceptable  to 
both  manufacturer  and  purchaser,  for  analysis. 
If  in  this  analysis  the  chemical  composition  of 
the  zincs  analyzed  is  found  to  be  in  accordance 
with  this  specification,  the  zincs  furnished  will 
be  accepted  and  the  cost  of  the  analysis  shall  be 
paid  by  the  purchaser.  If  the  chemical  com- 
position is  not  found  to  be  in  accordance  with 
this  specification,  all  expenses  in  connection 
with  the  analysis  including  the  loss  on  the  zincs 
analyzed  shall  be  borne  by  the  manufacturer. 

The  manufacturer  shall  be  advised  of  all  ma- 
terial rejected  as  a  result  of  chemical  analysis 
or  physical  tests,  and  if  at  the  expiration  of  two 
weeks  no  instructions  are  received  for  the  return 
of  same,  the  rejected  material  shall  be  returned 
at  the  risk  of  the  manufacturer,  he  paying  the 
freight  in  both  directions  in  either  case. 

The  payment  for  zincs  shall  be  based  upon 
the  net  weight  received. 

6.  Zincs  must   be  carefully   and   securely 
packed  in  shavings  or  sawdust  in  a  stout  barrel 
or  box,  in  lots  not  to  exceed  fifty  (50)  each. 
The  name  of  the  manufacturer  and  the  name 
of  the  consignee,  together  with  the  destination; 
number  of  zincs  contained  in  the  package  and 
the  purchase  order  number  must   be~pfeinly 
marked  on  the  outside  of  each  package. 

All  zincs  broken  in  transit  on  account  of  not 
being  properly  packed  will  be  returned  to  the 
manufacturer,  who  must  promptly  replace 
same  free  of  cost  to  the  purchaser. 

7.  Thumb  screws  for  binding  poets  shall  be 
furnished  only  when  specified 

When  furnished,  each  box  or  barrel  must  con- 
tain at  least  as  many  thumb  screws  as  there  are 
lines,  the  thumb  screws  being  wrapped  aepa- 
rately  and  tied  to  one  at  the  zincs  just  under 
the  cover- 


ZINC 

fcm  SUAVITY  BATTCRV 

R.  S.  A. 


ELECTRIC   INTERLOCKING  HANDBOOK 


291 


R.  S.  A.  COPPERS 

GRAVITY  PRIMARY  BATTERY 

R.  S.  A.  plan  1088.     Issue  October,  1911. 


ISSUE:  1911 


SPECIFICATION 

1.  MATERIAL,     (a)  Coppers  shall  be  two-leaf  or  three-leaf  as  specified 
and  shall  conform  to  the  above  drawing.     Leaves  shall  be  No.  30  B  &  S 
gauge,  hard  rolled  bright  copper  not  less  than  ninety-eight  (98)  per  cent, 
pure. 

(6)  Lead  wire  shall  be  No.  14  B  &  S  gauge,  solid  soft  drawn  copper,  insu- 
lated throughout  the  entire  length,  except  one  (1)  inch  at  each  end.  The 
insulation  shall  consist  of  a  three-sixty-fourths  (%4>  inch  wall  of  rubber, 
shall  adhere  tightly  to  the  wire  and  shall  be  of  a  character  suitable  to  with- 
stand the  action  of  the  battery  solution.  Insulation  on  ends  of  wire  to  be 
trimmed  either  tapered  or  square,  and  in  this  operation  the  wire  must  not 
be  scored. 

(c)  End  of  wire  attached  to  copper  must  be  thoroughly  cleaned  and  tightly 
riveted  as  shown  with  a  rivet  having  a  three-eighths  (%)  inch  head  and  a 
washer  three-eighths  (%)  inch  in  outer  diameter.  Both  rivets  and  washer 
shall  be  copper  not  less  than  ninety-eight  (98)  per  cent.  pure. 

2.  PACKINO    AND    MARKING.     Copper  shall  be  carefully  and  securely 
packed  in  lots  of  one-hundred  (100)  each,  or  fifty  (50)  if  so  specified,  and 
the  purchase  order  number,  contents  of  package,  name  of  manufacturer 
and  name  and  address  of  consignee  shall  be  plainly  marked  on  the  outside 
of  each  package. 

3.  INSPECTION    AND    ACCEPTANCE.     One  copper  taken  at  random  from 
each  fifty  (50)  or  fraction  thereof  shall  be  examined  and  tested.     The  results 
of  this  examination  shall  determine  whether  the  lots  so  represented  will  be 
accepted.     If  the  samples  are  found  to  meet  this  specification,  the  material 
will  be  accepted.     If  any  of  the  samples  fail  to  meet  this  specification,  the 


he  paying  the  freight  in  both  directions. 


292 


GENERAL  RAILWAY  SIGNAL  COMPANY 


R.  S.  A.  BATTERY   CHUTES 
R.  S.  A.  plan  1230.      Issue  December,  1912. 

12283 — i  i — 12292 


12283- 


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NOTE 

WHEN  ORDERING 
APPARATUS  OR 
PARTS  SHOWN  ON 
THIS  PlAN  GIVE 
NUMBER  AND 
NAME  APPEARING 

, 

, 

-12294 

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u 

-12286 

-12298 

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. 

3 

ASSEMBLY  OF  SINGLE  CHUTES         ASSEMBLY  OF  DOUBLE  CHUTES 

12301  =  6   FT.  CHUTE                                 12303  =  6    FT.  CHUTE 

12302  =  6    FT.              [WITH   12278]           12304=6   FT.                [WITH    i227io  -  12293] 

12305  =  7    FT.                                             12307  =  7   FT. 
12306  =  7    FT-                [WITH    12278]            12308=7   FT.                  [WITH    ,227iO  -  12295] 

12309  -8    FT.                                           123011=8  FT. 
123010=8    FT.                [WITH    i2?78J            123012^8   FT.                  [WITH    I227i0  -  12297] 

123013  =  9    FT.         '                                      123015  =  9    FT. 

123014=9    FT.               [WITH    i2278]           123016  =  9   FT,                 [WITH   i227ifl  -  1?299] 

ELECTRIC  INTERLOCKING  HANDBOOK 


293 


CARE  OF  THE  CELL 

In  making  renewals,  the  jars  should  be  well  washed,  being 
scoured  until  they  are  transparent.  The  elements  should  be 
cleaned  and  replaced  in  the  jar  with  clean  cop- 
per sulphate  crystals;  the  cell  should  then  be 
filled  to  a  point  just  below  the  bottom  of  the 
zinc  element  with  water  and  then  within  one- 
half  inch  of  the  top  of  the  jar  with  clear  zinc 
sulphate  taken  from  the  top  of  the  old  cell  — 
this  in  order  to  start  a  strong  chemical  action 
and  have  the  cell  available  for  immediate  service. 

The  cell  should  be  inspected  every  two  weeks 
and  the  residue  which  has  formed  on  the  zinc 
element  be  scraped  off.  At  the  same  time  the 
maintainer  should  check  the  specific  gravity  of 
the  electrolyte.  The  best  operation  of  the  cell 
will  be  secured  by  keeping  the  density  of  the  solu- 
tion at  about  twenty  degrees  Baume  (see  page 
384),  and  under  no  condition  should  it  exceed 
thirty  degrees;  the  density  can  be  lowered  by 
dipping  out  some  of  the  solution  and  refilling  the 
cell  with  water. 

The  bottom  of  the  zinc  element  should  be  main- 
tained about  two  and  one-half  inches  above  the 
level  of  the  copper  sulphate  crystals. 

The  ampere  output  of  the  cell  falls  off  consid- 
erably with  a  decrease  in  temperature.  Under  no 
conditions  should  the  cell  be  exposed  to  a  tem- 
perature below  thirty-two  degrees  Fahr.,  as  the 
solution  congeals  at  slightly  below  that  point  and 
freezes  with  a  further  reduction  in  temperature, 
this  interrupting  the  action  of  the  cell  and  in  a 


FIG. 250.  SEC-  great  many  cases  breaking  the  jar.  When  installed 
TION  OP  SIN-  outside  of  the  interlocking  station  the  cells  are 
GLE  BATTERY  housed  in  battery  chutes  or  wells  set  in  the 
CHUTE  WITH  grOund  to  place  them  beyond  the  reach  of  frost, 

the  proper  depth  of  the  housing  depending  on 

climatic  conditions. 


THE   DRY   CELL 

USES 

The  dry  cell  is  most  commonly  used  in  connection  with 
circuits  which  are  only  closed  momentarily,  or  for  a  few  seconds 
at  infrequent  intervals.  It  is  employed  for  such  purposes  as 
operating  annunciators,  buzzers,  etc.,  and  sometimes  in  the 
ignition  circuit  of  gasoline  engines. 


294  GENERAL  RAILWAY  SIGNAL  COMPANY 


DESCRIPTION 

The  cell  is  contained  in  a  zinc  shell  which  forms  one  ele- 
ment; the  other  element  consists  of  a  stick  of  carbon  set  in 
the  center  of  the  cell.  The  zinc  shell  is  usually  lined  with 
several  thicknesses  of  blotting  paper  and  the  remaining  space 
around  the  carbon  element  filled  with  a  mixture  of  carbon, 
manganese  dioxide,  sawdust,  or  other  absorbent  substance. 
This  mixture  is  then  saturated  with  a  solution  of  sal  ammoniac 
(muriate  of  ammonia)  and  water,  and  the  top  of  the  cell  sealed 
with  wax  or  pitch.  To  insulate  the  zinc  shell  from  adjacent 
cells,  metal  pipes,  etc.,  a  cylindrical  pasteboard  cover  is  fur- 
nished covering  the  sides  and  bottom  of  the  cell. 

The  cell  has  an  approximate  E.  M.  F.  of  1.5  volts  which  falls 
off  after  the  cell  has  been  in  service  for  some  time.  The 
internal  resistance  is  about  .075  ohm.  The  cell  polarizes  very 
quickly  when  on  short  circuit,  giving  less  and  less  current 
as  it  becomes  more  polarized,  until  it  finally  refuses  to  deliver 
current  at  all ;  the  cell  takes  some  time  to  recover  when  fully 
polarized. 

Exhaustion  of  the  cell,  except  when  polarized,  is  usually 
due  to  the  sal  ammoniac  having  been  entirely  consumed. 
The  zinc  container  is  gradually  consumed  by  the  action  of  the 
cell,  this  resulting  in  "puncturing,"  or  the  eating  through  in 
spots,  of  the  zinc. 

CARE  OF  THE  CELL 

The  cell  practically  requires  no  care  other  than  keeping  it 
in  a  dry  place  which  has  an  even  temperature  of  about 
seventy  degrees  Fahr.  Temperatures  below  this  will  limit  the 
amount  of  current  which  can  be  drawn  from  the  cell,  while  a 
greater  temperature  materially  reduces  the  cell's  life  through 
drying  up  the  sal  ammoniac. 

The  cell  is  in  reality  a  wet  cell,  sealed  to  prevent  the  paste 
from  drying  out.  If  the  cell  does  actually  become  dry  it  will 
not  produce  any  current,  but  if  the  elements  have  not  been 
worn  out  this  can  be  overcome  by  boring  a  hole  in  the  top  of 
the  cell  and  soaking  it  in  water  for  two  or  three  days. 

Care  should  be  taken  to  avoid  handling  the  cells  roughly,  as 
the  contents  of  the  cell  are  apt  to  become  broken  away  from 
the  carbon  electrode,  this  resulting  in  an  increase  of  the  internal 
resistance  of  the  cell  and  a  consequent  reduction  in  the  current 
output. 

EDITOR'S   NOTE 

Articles  on  primary  cells,  pages  285,  288  and  293,  based  on 
data  furnished  by  National  Carbon  Co, 


SECTION  XIII 


WIRE,  TRUNKING   AND   CONDUIT 


COVERING  INSTALLATION  PRACTICE, 
TABLES  OF  PHYSICAL  PROPERTIES  OF 
WIRE,  REQUIRED  SIZES  OF  CONTROL 
AND  COMMON  WIRES,  TRUNKING  CON- 
STRUCTION, AND  THE  CARRYING  CA- 
PACITIES OF  TRUNKING  AND  CONDUIT 


WIRE  AND  WIRING 


EXTRACTS  FROM   R.  S.  A    SPECIFICATIONS  FOR 

ELECTRIC   INTERLOCKING  (1910) 
521.  SIZE 

(a)  Wires  shall  be  of  sufficient  size  to  permit  operation 
of  switch  and  signal  mechanism  in  accordance  with  pre- 
vious specifications. 

(6)  Rubber-covered  wire  smaller  than  number  fourteen 
(14)  B.  &.  S.  gauge  shall  not  be  used. 

(c)  Hard-drawn  copper  line  wire  shall  not  be  smaller 
than  number  ten  (10)  B.  &  S.  gauge. 

(d)  No  common  return  wire  shall  be  less  than  number 
twelve  (12)  B.  &  S.  gauge. 

(e)  In  submarine  cable  work  spare  wires  up  to  twenty- 
five  (25)  per  cent,  of  the  number  in  use  shall  be  provided 
as  specified.     When  spare  wires  are  required  in  other  than 
cable  work  the  number  and  size  shall  be  specified. 

( / )  Numbers  and  sizes  of  track  circuit  connections 
shall  be  as  follows : 

No.  of  B.  &  S. 

conductors  gauge 

1.  Track  batteries  to  rail one  (1)  nine  (9)  or. 

2.  Relays  to  rail one  (1)  nine  (9)  or. 

3.  Fouling  shunt  connections  . .  .two  (2)  nine  (9)  or.  .  .(.) 

4.  Switch    circuit    controller 

connections two  (2)  nine  (9)  or ...(.) 

5.  Wire    from    trunking    to 

track  batteries  in  chutes, 

stranded twelve  (12)  or ...(.) 

(g)  Wires  connected  to  track  shall  be  rubber-covered 
soft-drawn  copper. 

525.  WIRING 

(a)  Wires  in  trunking,  chases  or  conduits  shall  be  laid 
loosely  without  stretching  or  crowding. 

(6)  Not  more  than  two  (2)  wires  shall  be  connected  to 
one  (1)  binding  post  or  terminal  screw. 

(c)  Unless  otherwise  specified,  all  wires  shall  be  run  as 
separate  conductors. 

526.  COMMON  RETURN 

(a)  Reductions  in  size  of  common  wire  and  connec- 
tions to  pole  lines  shall  be  made  in  junction  boxes. 

(6)  Connections  between  branches  and  main  common 
wires  shall  be  made  in  junction  boxes. 

NOTE. —  Wire  sizes  given  in  (/)  taken  from  R.  S.  A.  Automatic  Block 
Signal  Specifications    (521-/  dated  1913). 


298  GENERAL  RAILWAY  SIGNAL  COMPANY 


(c)  Unless  otherwise  specified,  common  return  wires 
shall  be  continuous  without  joints  or  breaks  from  inter- 
locking machine  to  the  limits  of  the  interlocking  plant. 

527.  JOINTS  IN  WIRE 

(a)  Wires  shall,  as  far  as  practicable,  be  continuous 
without  joints  or  breaks  between  interlocking  machine 
and  the  unit  operated ;  joints  when  made  shall  be  in  junc- 
tion boxes,  and  only  made  on  permission  from  the  Engi- 
neer. 

(6)  In  making  joints,  braid  shall  be  pulled  back  one  (1) 
inch  from  end  of  rubber  on  each  side  of  splice,  and  rubber 
cut  with  knife  held  at  an  angle  of  approximately  thirty 
(30)  degrees  with  axis  of  wire,  as  one  would  sharpen  a 
pencil. 

(c)  After  removing  rubber,   wire  shall  be  thoroughly 
cleaned,  care  being  taken  to  prevent  injury  from  small 
cuts  or  nicks. 

(d)  Wire,  after  being  cleaned,  shall  be  twisted  together 
in  the  form  of  a  regular  line  wire  splice,  turns  being  spaced 
approximately  one-sixty-fourth  (Ve4)  inch. 

(e)  Joints  shall  then  be  soldered  by  pouring  on  them,  or 
dipping  them  into,  melted  solder,  a  non-corrosive  rosin 
flux  being  used.     After  soldering,  joints  shall  be  painted 

with  insulating  paint  or  with 

compound. 

(7)  Joints  shall  then  be  covered  with  two  (2)  layers  of 

insulating  tape  between  ends  of  braid,  which 

tape  shall  be  heated  sufficiently  to  form  a  tight  covering, 
but  not  enough  to  injure  the  quality  of  the  material.   Coat- 
ing  of insulating  paint   or com- 
pound shall  be  put  on  over  insulating  tape  and  two  (2) 

layers  of adhesive  or  friction  tape  shall  be 

applied,  after  which  the  outside  of  the  joint  is  to  be  painted 
with insulating  paint. 

528.  FUSES 
Material. 

(a)  Fuses  shall  be  of  the  enclosed  type. 
Field  work. 

(6)  The  necessary  fuses  to  properly  protect  all  appa- 
ratus and  circuits  shall  be  installed. 

(c)  Fuses   outside    of    buildings    shall    be   enclosed    in 
weatherproof  boxes. 

(d)  In  the  lighting  circuits,  a  fuse  shall  be  provided  in 
the  circuit  to  each  signal  lamp;    in  the  circuit  to  each 
set  of  lamps  on  a  mast;    in  each  branch  circuit  leaving 
the  mains,  and  in  each  set  of  mains  leaving  the  switch- 
board. 

(e)  Double  pole  fuse  cut-out  shall  be  provided  for  each 
circuit  on  the  power  board. 


ELECTRIC   INTERLOCKING   HANDBOOK  299 


(/)  An  additional  double  pole  fuse  cut-out  shall  be 
placed  in  storage  battery  leads  as  near  as  possible  to  the 
battery  terminals. 

530.  TAGS. 
Material. 

(a)  Tags  shall  be  made  of  vulcanized  sheet  fibre,  not 
less  than  one-sixteenth  (He)  inch  thick,  firmly  attached  to 
the  wire  by  the  best  quality  yacht  marline  one-sixteenth 
(Vie)  inch  in  diameter. 

(6)  The  tag  shall  have  a  stamped  imprint  to  show  the 
function  of  the  wire. 
Field  work. 

(c)  Wires  shall  be  tagged  at  all  junction  boxes,  switches, 
signals,  relay  boxes,  arrester  boxes,  and  at  all  line  wire 
connections,  unless  otherwise  specified. 


FLUXES  FOR  SOLDERING  AND  WELDING 

Iron, Borax. 

Tinned  Iron,     ....   Resin. 
Copper  and  brass,    .    .   Sal  ammoniac. 

Zinc, Chloride  of  zinc. 

Lead, Tallow  or  resin. 

Lead  and  tin  pipes, .    .   Resin  and  sweet  oil. 

Steel, Pulverize  —  1  part  sal  ammoniac,  10 

parts    borax,    and    fuse    until    clear. 

When  solidified,  pulverize  to  powder. 


INSTRUCTIONS    FOR    SPLICING,    SOLDERING,    AND 
TAPING  JOINTS  IN  RUBBER-COVERED  WIRE 

STRIPPING  THE  INSULATION    • 

When  stripping  the  insulation,  the  knife  blade  should  be 
held  at  such  an  angle  as  one  would  use  in  sharpening  a  pencil ; 
do  not  hold  the  blade  at  right  angles  to  the  wire,  as  the  wire  is 
apt  to  be  nicked  if  this  is  done. 

SPLICING  STRANDED  WIRE  TO  STRANDED  WIRE 

Remove  the  insulation  carefully  from  the  end  of  each 
wire  for  three  to  four  inches,  according  to  the  size  of  the 
wire.  Remove  the  braid  about  one  inch  further  back  from 
the  bare  portion  of  the  wire,  being  careful  not  to  cut  the 
rubber.  If  the  strands  become  untwisted,  twist  together  and 
clean  thoroughly  of  rubber,  leaving  the  wire  bright. 


300 


GENERAL  RAILWAY  SIGNAL  COMPANY 


Starting  as  shown  in  Fig.  251,  twist  the  wires  together  in  the 
regular  manner  of  making  a  line  wire  joint;  cut  off  surplus 
wire,  as  shown  in  Fig.  252,  and  solder  and  tape  as  described 
under  "Soldering"  and  "Taping."  See  Figs.  253  and  254 
for  appearance  of  soldered  and  finished  joints. 


FIG.  251 


FIG.  252 


FIG.  253 


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FIG.  254 
SPLICING  STRANDED  WIRE  TO  STRANDED  WIRE 

SPLICING  STRANDED  WIRE  TO  SOLID  WIRE 

Remove  the  insulation  from  the  solid  wire  for  about  one  and 
one-half  inches  and  from  the  stranded  wire  for  three  to  four 
inches,  according  to  the  size  of  the  wire.  Remove  the  braid 
for  about  one  inch  back  from  the  bare  portion  of  the  wire. 
being  careful  not  to  cut  the  rubber. 


FIG.  255 


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FIG.  256 

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FIG.  257 


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FIG.  258 
SPLICING  STRANDED  WIRE  TO  SOLID  WIRE 


ELECTRIC   INTERLOCKING  HANDBOOK  301 

Clean  both  stranded  and  solid  wires,  leaving  them  bright. 
If  the  strands  of  the  stranded  wire  become  untwisted,  twist 
them  together  and  starting  as  shown  in  Fig.  255,  twist  the 
stranded  wire  around  the  solid  wire,  leaving  about  the  thick- 
ness of  the  stranded  wire  between  the  turns  for  about  two 
turns,  and  then  wind  close;  cut  off  the  solid  wire,  leaving 
enough  to  turn  an  eye  around  the  stranded  wire  as  shown  in 
Fig.  256.  Solder  and  tape  as  described  under  "  Soldering  " 
and  "  Taping." 


FIG.  259 


FIG.  260 


FIG.  262 
SPLICING  SOLID  WIRE  TO  SOLID  WIRE 

SPLICING  SOLID  WIRE  TO  SOLID  WIRE 

The  insulation  should  be  removed  from  four  to  six  inches 
from  the  end  of  each  wire.  Remove  the  braid  for  about  one 
inch  from  the  ends  of  the  insulation.  The  bare  wire  should 
be  thoroughly  cleaned  of  all  rubber.  Lay  the  two  wires 
together  so  that  the  distance  between  the  insulations  will  be 
about  one  and  one-half  or  one  and  three-fourths  inches, 
as  shown  in  Fig.  259.  Hold  the  middle  of  the  joint  with 
the  pliers  and  twist  the  end  of  one  wire  around  the  other, 
leaving  about  one  sixty-fourth  inch  between  turns  for  solder 
to  run  in,  as  shown  in  Fig.  260.  This  winding  should  stop 
when  the  insulation  is  reached  and  the  surplus  wire  then  be 
cut  off.  The  other  end  should  be  wound  in  this  same  man- 
ner and  the  middle  part  twisted  for  three  or  four  turns. 
Solder  and  tape  the  joint  as  described  under  "Soldering"  and 
"Taping." 


302 


GENERAL  RAILWAY  SIGNAL  COMPANY 


FIG.  263 


FIG.  264 


FIG.  265 


V  V  \ 

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FIG.  266 
MAKING  T  JOINTS  IN  SOLID  WIRE 


ELECTRIC   INTERLOCKING   HANDBOOK 


MAKING  T  JOINTS  IN  STRANDED  OR  SOLID  WIRES 

Remove  the  insulation  from  the  continuous  wire  where  the 
joint  is  to  be  made  for  about  one  and  one-fourth  inches  and 
the  braid  for  about  one  inch  beyond  the  ends  of  the  insula- 
tion. Remove  the  insulation  from  the  end  of  the  tap  wire 
in  the  same  manner  as  described  for  joints  in  solid  wire.  Lay 
the  end  of  the  tap  wire  across  the  bare  part  of  the  continuous 
wire  as  shown  in  Fig.  263  and  wrap  around  the  continuous 
wire  as  shown  in  Fig.  264,  stopping  when  the  insulation  is 
reached.  Cut  off  the  surplus  wire  and  solder  and  tape  as 
described  under  "Soldering"  and  "Taping." 


FIG.  267.     PARALLEL,  JOINTS 

PARALLEL  JOINTS 

When  two  or  more  joints  come  side  by  side,  as  sometimes 
happens  in  parallel  wires,  one  joint  should  be  lapped  beyond 
the  other  so  as  to  leave  at  least  three-fourths  inch  of  the 
original  insulation  between  the  joints,  as  shown  in  Fig.  267. 

SOLDERING 

In  soldering  it  is  recommended  that  an  approved  soldering 
compound  in  stick  form,  such  as  Allen's  Soldering  Compound, 
be  used.  Joints  should  be  soldered  by  pouring  melted  solder 
over  the  joint  or,  if  impractical  to  do  this,  the  work  should  be 
done  with  a  well-tinned  soldering  copper  having  sufficient 
heat  to  thoroughly  heat  the  entire  joint.  Never  use  an  open 
flame  for  soldering  joints. 


FIG.  268 


FIG.  269 
METHOD  OP  TAPING 

TAPING 


All  joints  whether  for  inside  or  outside  work  must  be  taped 
with  Okonite  tape  (or  its  equivalent)  in  the  following  manner: 
The  tape  should  first  be  stretched  to  insure  its  laying  tight  to 
the  wire.  Start  the  tape  close  up  to  the  rubber  insulation 
(see  Fig.  268)  and  wind  with  a  half  lap  over  the  joint  and  rubber 


304  GENERAL  RAILWAY   SIGNAL  COMPANY 


insulation  to,  but  not  over,  the  braid  at  the  end ;  thence  back 
over  joint  and  rubber  insulation  to,  but  not  over,  the  braid  on 
the  other  end,  and  then  back  to  where  taping  was  started 
(see  Fig.  269).  Warm  the  joint  sufficiently  to  soften  the  tape 
slightly,  squeezing  the  tape  down  with  the  hand  to  make  it 
adhere  closely  to  the  rubber  insulation  and  to  itself. 

Black  friction  tape  of  good  quality  should  be  applied  over 
the  rubber  tape,  using  three-eighths  inch  tape  for  No.  16 
wire  or  smaller,  five-eighths  inch  tape  for  No.  14  to  No.  10 
wire  inclusive,  and  three-fourths  inch  tape  for  wires  larger 
than  No.  10.  Start  the  tape  near  the  middle  of  the  joint  and 
using  a  half  lap,  wind  about  one-half  inch  beyond  the  braid 
at  one  end;  then  back  to  one-half  inch  beyond  the  braid 
at  the  other  end,  thence  back  and  finish  near  the  middle  of  the 
joint.  In  order  to  make  a  neat,  strong  joint,  it  is  necessary  to 
draw  the  tape  tight  during  the  whole  operation. 

See  Figs.  254,  258,  262,  and  266  for  appearance  of  finished 
joints.  Care  should  be  taken  to  keep  the  nands  free  from  oils 
or  grease,  as  these  will  injure  both  the  rubber  tape  and  the 
adhesive  qualities  of  the  friction  tape. 


ELECTRIC  INTERLOCKING  HANDBOOK 


305 


COMPARISON   OF   BROWN   &    SHARPE   AND    BIRMINGHAM 
WIRE    GAUGES 


BROWN  &  SHARPE  GAUGE 

BIRMINGHAM  WIRE  GAUGE 

Gauge 
Num- 
ber 

Diam. 
in 
Inches 

Area 

Gauge 
Num- 
ber 

Diam. 
in 
Inches 

Area 

Circular 
Mils 

Square 
Inches 

Circular 
Mils. 

Square 
Inches 

0000 

.4600 

211600 

.166190 

0000 

.4540 

206100 

.  161883 

000 

.4096 

167800 

.131790 

000 

.4250 

180600 

.141863 

00 

.3648 

133100 

.  104518 

00 

.3800 

144400 

.113411 

0 

.3249 

105500 

.082887 

0 

.3400 

115600 

.090792 

1 

.2893 

83690 

.065732 

1 

.3000 

90000 

.070686 

2 

.2576 

66370 

.052128 

2 

.2840 

80660 

.063347 

3 

.2294 

52630 

.041339 

3 

.2590 

67080 

.052685 

4 

.2043 

41740 

.032784 

4 

.2380 

56640 

.044488 

5 

.1819 

33100 

.025999 

5 

.2200 

48400 

.038013 

6 

.1620 

26250 

.020618 

6 

.2030 

41210 

.032365 

7 

.1443 

20820 

.01635J 

7 

.1800 

32400 

.025447 

8 

.1285 

16510 

.012967 

8 

.1650 

27230 

.021382 

9 

.1144 

13090 

.010283 

9 

.1480 

21900 

.017203 

10 

.1019 

10380 

.008155 

10 

.1340 

17960 

.014103 

11 

.0907 

8234 

.006467 

11 

.1200 

14400 

.011310 

12 

.0808 

6530 

.005129 

12 

.1090 

11880 

.009331 

13 

.0720 

5178 

.004067 

13 

.0950 

9025 

.007088 

14 

.0641 

4107 

.003225 

14 

.0830 

6889 

.005411 

15 

.0571 

3257 

.002558 

15 

.0720 

5184 

.004072 

16 

.0508 

2583 

.002029 

16 

.0650 

4225 

.003318 

NOTE.— 1  Mil.^.OOl  inch.     1  Circular  Mil. = Area  of  1  Mil.  diameter. 


306 


GENERAL  RAILWAY  SIGNAL  COMPANY 


SOFT-DRAWN    COPPER   WIRE 


RESISTANCE  IN 

WEIGHT  IN  POUNDS 

Number 

Diameter 

OHMS  AT  68°  F 

Bare  Wire 

R.  S.  A. 

Gauge 

in  Inches 

Per 
1000  Ft. 

Per 

Mile 

Per 

1000  ft. 

Per 
Mile 

Per 
1000  ft. 

Per 
Mile 

0 

.325 

.10 

.52 

320 

1687 

525 

2772 

1 

.289 

.12 

.65 

253 

1337 

423 

2233 

2 

.258 

.16 

.82 

201 

1062 

358 

1890 

4 

.204 

.25 

1.31 

126 

667 

224 

1183 

6 

.162 

.39 

2.08 

79 

419 

158 

834 

8 

.128 

.63 

3.31 

50 

264 

116 

613 

9 

.114 

.79 

4.18 

40 

209 

85 

449 

10 

.102 

1.00 

5.27 

31 

166 

80 

422 

12 

.081 

1.59 

8.37 

20 

104 

61 

322 

14 

.064 

2.52 

13.31 

12 

66 

50 

264 

16 

.051 

4.01 

21.17 

8 

41 

32 

169 

GALVANIZED   IRON    AND   STEEL   WIRE 


fcPQ 

OS 

BREAKING 
WEIGHTS 
POUNDS 

RESISTANCE  PER 
MILE  IN  OHMS. 
AT  68°  F. 

WEIGHT  IN  POUNDS 

Bare  Wire 

Double  Braid 
Weather- 
proof 

Triple  Braid 
Weather- 
proof 

Iron 

Steel 

E.B.B 

B.B. 

Steel 

Per 
1000 
ft. 

Per 

Mile 

Per 

1000 

ft. 

Per 

Mile 

Per 
1000 
ft. 

Per 
Mile 

0 

.340 

4821 

9079 

2.93 

3.42 

4.05 

304 

1607 

1 

.300 

3753 

7068 

3.76 

4.4 

5.2 

237 

1251 

2 

.284 

3363 

6335 

4.19 

4.91 

5.8 

212 

1121 

4 

.238 

2361 

4449 

5.97 

6.99 

8.26 

149 

787 

163 

860 

178 

940 

6 

.203 

1719 

3237 

8.21 

9.6 

11.35 

109 

573 

126 

665 

140 

740 

8 

.165 

1134 

2138 

12.42 

14.53 

17.18 

72 

378 

89 

470 

100 

525 

9 

.148 

915 

1720 

15.44 

18.06 

21.35 

58 

305 

76 

400 

85 

450 

10 

.134 

750 

1410 

18.83 

22.04 

26.04 

47 

250 

66 

350 

76 

400 

12 
14 

.109 
.083 

495 

288 

933 
541 

28.4633.3 
49.0857.44 

39.36 

67.88 

31 

18 

165 
96 

43 
28 

225 
145 

49 
33 

260 
175 

16 

.065 

177 

332 

80.03J93.66 

110.7 

11 

59 

... 

... 

ELECTRIC   INTERLOCKING   HANDBOOK 


307 


HARD-DRAWN   COPPER  WIRE 


CO 

RESISTANCE 

WEIGHT  IN  POUNDS 

«y 

PQ  w> 
*-  § 

Diam- 
eter 
Bare 

Break- 
ing 
Weight 

IN  OHMS  AT 
68°  F. 

Bare  Wire 

Double  Braid 
Weatherproof 

Triple  Braid 
Weath'rprool 

a 
{ 

Wire 
in  In. 

in 
Pounds 

Per 
1000 
Ft. 

Per 
Mile 

Per 
1000 
Ft. 

Per 

Mile 

Per 
1000 
Ft. 

Per 

Mile 

Per 
1000 
Ft. 

Per 

Mile 

0 

.325 

4973 

.10 

.53 

320 

1687 

377 

1989 

407 

2150 

i 

.289 

3943 

.13 

.67 

253 

1337 

294 

1553 

316 

1670 

2 

.258 

3127 

.16 

.85 

201 

1062 

239 

1264 

260 

1370 

4 

.204 

1967 

.26 

1.35 

126 

667 

151 

795 

164 

865 

6 

.162 

1237 

.41 

2.14 

79 

419 

100 

529 

112 

590 

8 

.128 

778 

.64 

3.39 

50 

264 

66 

349 

75 

395 

9 

.114 

617 

.81 

4.29 

40 

209 

54 

283 

62 

325 

10 

.102 

489 

1.02 

5.41 

31 

166 

46 

241 

53 

280 

12 

.081 

307 

1.62 

8.60 

20 

104 

30 

158 

35 

185 

14 

.064 

193 

2.20 

11.59 

12 

66 

20 

107 

25 

130 

16 

.051 

133 

4.12 

21.74 

8 

41 

16 

83 

20 

105 

COPPER-CLAD   WIRE  — GRADE  "A" 
BBIGHT,  HARD  DRAWN 


00 

RESISTANCE 

WEIGHT  IN  POUNDS 

«8 

n'S) 

u  3 

Diam- 
eter 
Bare 

Break- 
ing 
Weight 

IN  OHMS  AT 
60°  F. 

Bare  Wire 

Double  Braid 
Weatherproof 

Triple  Braid 
Weath'rproof 

£o 

• 

5 

Wire 
in  In. 

in 
Pounds 

Per 
1000 
Ft. 

Per 

Mile 

Per 

1000 
Ft. 

Per 
Mile 

Per 
1000 
Ft. 

Per 
Mile 

Per 
1000 
Ft. 

Per 

Mile 

0 

.325 

5472 

.32 

1.70 

293 

1546 

350 

1850 

381 

2011 

i 

.289 

4798 

.41 

2.14 

232 

1226 

273 

1443 

295 

1560 

2 

.258 

3804 

.51 

2.70 

184 

972 

223 

1177 

243 

1283 

4 

.204 

2721 

.81 

4.29 

116 

611 

140 

740 

153 

810 

6 

.162 

1797 

1.29 

6.82 

73 

384 

94 

494 

105 

555 

8 

.128 

1187 

2.05 

10.84 

46 

242 

62 

327 

71 

373 

9 

.114 

984 

2.59 

13.68 

36 

192 

51 

266 

58 

308 

10 

.102 

780 

3.26 

17.24 

29 

152 

43 

227 

51 

266 

12 

.081 

512 

5.20 

27.43 

18 

96 

28 

149 

33 

176 

14 

.064 

334 

8.25 

43.60 

11 

60 

19 

101 

24 

127 

16 

.051 

216 

13.14 

69.40 

7 

38 

15 

80 

19 

102 

NOTE. — -Average  conductivity,  30  per  cent, 
per  cent. 


Minimum  conductivity,  27 


308 


GENERAL  RAILWAY  SIGNAL  COMPANY 


1 1 


b-    iO    •<*<    C^J 
•-<    rH    <N    <N 


iO  iO 


O    CD    r-t 


^O    iO 


t>.     t^ 


C^C^ 


O    O 


(N    CO    CO 


O    CO    !>• 


!>• 

(NC^IOOOOCO  TH  r-t  rH  <N 


o       *o       o       o       o       o 

^  Ci          t^»  *O  Cl  *-* 


<N  CM  CN 

i-l  <N  <M  CO  CO  CO  CO 


O  O  00  CO  O 
CO   CO  ^ 


!i 


&      .    £       .  ^2 

g      .     *       -     § 
«         03         Q 


.  <! 


<    .-<    -W    .«    - 


WWWPP03         03         03 


ELECTRIC  INTERLOCKING  HANDBOOK 


309 


COMMON   RETURN   WIRE 

DETERMINATION  OF  THE  REQUIRED  SIZE  WIRE  FOR  A  GIVEN 
LENGTH  OF  COMMON 


Max. 
Amps. 

NUMBER  OF  COMMON  WIRE,  B.  &  S.  GAUGE 

Max. 
Amps. 

I        I 

In 

14 

12 

10 

9 

8 

6 

4 

2 

1 

0 

00 

000 

in 

Com- 

Com- 

mon 

Ft. 

Ft. 

Ft. 

Ft. 

Ft. 

Ft. 

Ft. 

Ft. 

Ft. 

Ft. 

Ft. 

Ft. 

mon 

4.5 

503 

802 

1275 

1600 

2025 

3220 

5120 

8140 

10275 

129.50 

16300 

20550 

4.5 

6 

378 

603 

956 

1205 

1521 

2420 

3850 

6115 

7710 

974012250 

15450 

6 

7 

324 

517 

820 

1032 

1305 

2075 

3300 

5245 

6620 

835010050 

13250 

7 

9 

254 

404 

640 

807 

1020 

1620 

2560 

4100 

5160 

6525 

8210 

10350 

9 

10 

227 

361 

575 

724 

913 

1451 

2310 

3670 

4630 

5840 

7350 

9275 

10 

11.5 

197 

314 

503 

628 

792 

1260 

2010 

3190 

4125 

5075 

6390 

8500 

11.5 

13 

174 

278 

441 

555 

701 

1115 

1772 

2820 

3560 

4490 

5650 

7125 

13 

14 

162 

258 

410 

517 

654 

1040 

1650 

2620 

3300 

4170 

5250 

6625 

14 

16 

142 

226 

359 

453 

570 

907 

1445 

2295 

2890 

3650 

4600 

5800 

16 

18 

126 

202 

318 

410 

507 

806 

1280 

2040 

2570 

3240 

4085 

5150 

18 

20 

113 

181 

287 

362 

456 

726 

1155 

1835 

2312 

2920 

3680 

4630 

20 

22 

103 

164 

261 

329 

415 

660 

1150 

1670 

2120 

2660 

3345 

4215 

22 

24 

94 

151 

239 

301 

380 

605 

963 

1530 

1930 

2435 

3060 

3865 

24 

26 

139 

221 

278 

352 

560 

890 

1412 

1760 

2250 

2830 

3562 

26 

28 

129 

205 

258 

326 

518 

824 

1320 

1650 

2085 

2620 

3310 

28 

30 

120 

191 

241 

304 

485 

770 

1223 

1541 

1950 

2450 

3090 

30 

32 

179 

226 

285 

455 

724 

1145 

1445 

1825 

2300 

2900 

32 

34 

168 

213 

269 

427 

680 

1080 

1360 

1720 

2163 

2730 

34 

36 

160 

201 

254 

405 

644 

1020 

1290 

1625 

2045 

2580 

36 

38 

151 

190 

240 

383 

610 

965 

1220 

1540 

1935 

2440 

38 

40 

143 

181 

228 

364 

578 

917 

1158 

1460 

1840 

2320 

40 

42 

172 

217 

346 

550 

875 

1101 

1392 

1755 

2210 

42 

44 

164 

208 

331 

525 

835 

1053 

1330 

1672 

2110 

44 

46 

157 

198 

315 

500 

795 

1003 

1265 

1595 

2010 

46 

48 

151 

190 

303 

481 

765 

965 

1215 

1532 

1931 

48 

50 

145 

182 

290 

462 

734 

925 

1170 

1470 

1855 

50 

52 

175 

279 

443 

703 

887 

1120 

1410 

1775 

52 

54 

169 

269 

427 

680 

855 

1070 

1360 

1715 

54 

56 

163 

259 

412 

655 

825 

1040 

1312 

1655 

56 

58 

157 

250 

398 

633 

798 

1010 

1270 

1600 

58 

60 

152 

242 

385 

612 

770 

975 

1225 

1545 

60 

62 

235 

373 

594 

747 

945 

1188 

1500 

62 

64 

227 

362 

575 

725 

915 

1150 

1450 

64 

66 

220 

350 

556 

700 

886 

1130 

1405 

66 

68 

213 

338 

539 

679 

856 

1080 

1360 

68 

70 

207 

329 

524 

661 

835 

1050 

1325 

70 

72 

201 

320 

510 

643 

810 

1020 

1286 

72 

74 

196 

312 

495 

625 

788 

992 

1250 

7  • 

76 

191 

304 

483 

610 

770 

967 

1226 

76 

78 

186 

296 

471 

594 

750 

945 

1190 

78 

80 

181 

288 

459 

578 

730 

919 

1160 

80 

NOTE. — To  determine  maximum  return  amperes  in  common  wire,  add  the 
amperes  taken  by  all  functions  likely  to  be  operated  at  the  same  time. 


310 


GENERAL  RAILWAY  SIGNAL  COMPANY 


RELATIVE   COMPARISON   OF   COPPER   AND   ALUMINUM 
CONDUCTORS 


OF  EQUAL  LENGTH 
AND  CROSS  SECTION 

OP  EQUAL  LENGTH  AND  CONDUCTIVITY 

Conduc- 
tivity 

Resist- 
ance 

Cross 
Section 

Weight 

Tensile 
Strength 

Cost 

Copper 

100 

100 

100 

100.0 

100.0 

100 

Aluminum 

54 

185 

180 

54.0 

85.1 

185 

Aluminum 

55 

182 

176 

53.0 

83.5 

189 

Aluminum 

56 

179 

173 

52.0 

82.0 

192 

Aluminum 

57 

175 

170 

51.1 

80.6 

196 

Aluminum 

58 

172 

167 

50.2 

79.2 

199 

Aluminum 

59 

169 

164 

49.4 

77.9 

203 

Aluminum 

60 

167 

162 

48.6 

76.6 

206 

Aluminum 

61 

164 

159 

47.8 

75.3 

210 

Aluminum 

62 

161 

157 

47.0 

74.1 

213 

Aluminum 

63 

159 

154 

46.3 

72.9 

216 

CARRYING   CAPACITY   OF   INTERIOR   CONDUCTORS 

NATIONAL  ELECTRICAL  CODE 


B.  and  8.  Gauge 
Copper  98%  Con. 

CONCEALED  RUBBER 
COVERED  WIRES 

EXPOSED  WEATHERPROOF 
WIRES 

Amperes 

Amperes 

0000 

210 

312 

000 

177 

262 

00 

150 

220 

0 

127 

185 

1 

107 

156 

2 

90 

131 

4 

65 

92 

6 

46 

65 

8 

33 

46 

9 

28 

38 

10 

24 

32 

12 

17 

23 

14 

12 

16 

16 

6 

8 

NOTE. —  Permissible  heating  only  considered  in  above  figures. 


ELECTRIC   INTERLOCKING   HANDBOOK 


311 


DIMENSIONS   OF    RAILWAY   SIGNAL   ASSOCIATION    STANDARD 
RUBBER-COVERED    COPPER   WIRE 


Size  of  Wire 
B.  &  S.  Gauge 

Diameter  of 
Wire 
Inch 

Thickness  of 
Insulation 
Inch 

Thickness  of 
One  Braid 
Inch 

Total 
Diameter 
Inch 

0 

2*4t 

%4 

%4 

*%4 

1 

19/64 

%4 

%4 

8%4 

2 

17/64 

%4 

%4 

8%4 

4 

13/64 

%4 

2/84 

2%4 

6 

10/64 

%4 

2/64 

2%4 

8 

%4 

%4 

%4 

24/64 

9 

%4 

%4 

%4 

2V64 

10 

%4 

%4 

%4 

2%4 

12 

%4 

%4 

%4 

19/64 

14 

y84 

%4 

%4 

18/64 

16 

%4 

%4 

%4 

15/«4 

NOTE. —  For  each  additional  braid  add  four  sixty-fourths  inches  to  total 
diameter.  For  each  layer  of  tape  add  two  sixty-fourths  inches  to  total 
diameter. 


DIMENSIONS    OF    MANUFACTURER'S    ENGINEERS'    STANDARD 
RUBBER-COVERED   COPPER   WIRE 


Size  of  Wire 
B.  &  S.  Gauge 

Diameter  of 
Wire 
Inch 

Thickness  of 
Insulation 
Inch 

Thickness  of 
One  Braid 
Inch 

Thickness  of 
One  Tape 
Inch 

Total 
Diameter 

0 

21/64 

%4 

%4 

Vef 

4%4 

1 

19/64 

%4 

%4 

Ve4 

*V64 

2 

17/64 

%4 

%4 

V64 

8%4 

4 

!%4 

%4 

%4 

V64 

8V64 

6 

10/64 

%4 

%4 

%4 

2%4 

8 

%4 

%4 

%4 

%4 

2%4 

9 

7/64 

%4 

%4 

¥64 

2%4 

10 

%4 

%4 

%4 

fei 

22/64 

12 

%4 

%4 

%4 

V64 

2V64 

14 

%4 

%4 

%4 

V64 

2%4 

16 

%4 

V64 

2^ 

%4 

17/64 

NOTE. —  For  each  additional  braid  add  four  sixty-fourths  inches  to  total 
diameter.  For  each  additional  layer  of  tape  add  two  sixty-fourths  inches 
to  total  diameter. 


TRUNKING,  JUNCTION  BOXES  AND 
SUPPORTS 


EXTRACT  FROM  R.  S.  A.  SPECIFICATION  FOR 

ELECTRIC  INTERLOCKING  (1910) 
700.  TRUNKING 
Material. 

(/)  Trunking,  when  on  stakes  above  ground  and  run- 
ning parallel  with  the  track,  shall  not  be  placed  nearer 
than  six  (6)  feet  from  the  gauge  side  of  the  nearest  rail 
except  by  special  permission. 

(gr)  Local  conditions  shall  determine  the  height  of 
trunking  when  above  ground;  in  general,  when  trunking 
is  run  parallel  with  the  tracks,  bottom  of  trunking  shall 
be  placed  approximately  six  (6)  inches  above  ground. 

(i)  Nails  shall  not  be  driven  through  the  trunking  from 
the  inside  of  the  groove  nor  shall  they  be  driven  into  the 
groove  from  the  outside. 

(/)  Inside  corner  of  trunking,  at  turns,  must  be  rounded 
to  prevent  insulation  on  wires  being  injured. 

(fc)  Surfaces  of  trunking  that  are  to  be  painted  shall  be 
finished. 

(Z)  Not  less  than  one-third  (MO  of  the  capacity  of  the 
groove  shall  remain  free  for  the  further  installation  of 
wires. 

(ri)  As  specified,  capping  shall   be  securely  fastened  to 

trunking  with  {  gat®  Jj°oks  JGate  hooks  may  be  used  on 
main  runs  of  trunking  and  nails  on  cross  leads. 

703.  JOINTS  IN  TRUNKING 

(a)  Unless  otherwise  specified,  joints  in  grooved  trunk- 
ing shall  be  lapped,  the  ends  of  trunking  being  beveled  at 
an  angle  of  forty-five  (45)  degrees. 

(6)  Joints  in  built-up  trunking  shall  be  staggered. 

(e)  Joints  in  capping  shall  be  made  at  least  one  (1) 
foot  from  joints  in  trunking. 

705.  TRUNKING  SUPPORTS 
Material. 

(a)  Stakes  shall  be  made  of three  (3) 

inches  by  four  (4)  inches,  or  of  equivalent  circular  sec- 
tion and  of  sufficient  length  to  allow  them  to  be  placed  at 
least  two  (2)  feet  in  the  ground.  When,  due  to  local  re- 
quirements, stakes  of  a  greater  length  than  three  (3)  feet 
six  (6)  inches,  or  a  greater  cross  section  than  three  (3; 
inches  by  four  (4)  inches  will  be  necessary,  information  as 
to  the  number,  length,  and  cross  section  will  be  furnished 
by  the  Purchaser  to  the  Contractor. 


ELECTRIC  INTERLOCKING   HANDBOOK  313 


Field  work. 

(6)  Trunking  above  ground  shall  be  supported  on  stakes 
placed  not  more  than  five  (5)  feet  centers. 

(d)  Stakes  supporting  trunking  shall  be  placed  verti- 
cally and  extend  at  least  two  (2)  feet  below  the  surface  of 
the  ground,  unless  otherwise  specified. 

(e)  A  piece  of  capping  eight   (8)  inches  long  and  the 
width  of  the  trunking  shall  be  placed  between  the  trunk- 
ing and  each  stake. 

(/)  Each  joint  in  the  bottom  of  the  trunking  shall  be 
supported  by  a  stake. 

710.  JUNCTION  BOXES 

Material. 

(a)  Junction  boxes  shall  be  made  of and 

so  designed  that  terminals  will  be  kept  dry.     Each  junc- 
tion box  shall  be  fitted  with  a  cover,  hasp,  and  staple. 

(6)  Where  ten  (10)  or  less  wires  are  used,  junction 
boxes  shall  be  sixteen  (16)  inches  square  by  twenty  (20) 
inches  deep,  inside  dimensions,  and  shall  be  increased  six 
(6)  inches  in  length  for  each  ten  (10)  additional  connec- 
tions or  fraction  thereof  made  in  the  box. 
Field  work. 

(c)  Junction  boxes  shall  be  located  as  shown  on 

drawing and  at  a  height 

sufficient  to  allow  terminals  to  be  placed  at  least  six  (6) 
inches  above  top  of  trunking. 

(d)  Junction    boxes   shall    be    supported   in    the   same 
manner  as  the  trunking. 


314 


GENERAL  RAILWAY  SIGNAL  COMPANY 


TABLE    FOR    DETERMINING   REQUIRED    SIZE    OF    TRUNKING 


TRUNKING 

RUBBER-COVERED  COPPER  WIRE 
R.  S.  A.  SPECIFICATIONS 

Size 
See 
Fig.  270 

Size  of 
Groove 
Inches 

Area  of 
Groove 
Sq.  in. 

No. 
0 

No. 
1 

No. 

2 

No. 

4 

No. 
6 

No. 
8 

No. 
9 

No. 
10 

No. 
12 

No. 
14 

No. 
16 

1 

1     xl 

1.00 

1 

1 

1 

2 

3 

3 

4 

5 

5 

5 

7 

2 

1%  x  iy2 

1.87 

2 

2 

3 

5 

6 

6 

8 

9 

9 

10 

14 

3 

1     x2 

2.00 

2 

2 

3 

8 

6 

7 

9 

10 

10 

11 

15 

4 

iy2xiy2 

2.25 

2 

3 

3 

6 

7 

8 

10 

11 

11 

12 

17 

5 

iy2  x  1% 

2.62 

2 

3 

4 

6 

8 

9 

12 

13 

13 

14 

19 

6 

1V2X2 

3.00 

3 

4 

4 

7 

9 

10 

13 

14 

15 

16 

22 

7 

1%  x  1% 

3.06 

3 

4 

5 

7 

9 

10 

14 

14 

15 

16 

22 

8 

2     x2 

4.00 

4 

5 

6 

10 

12 

13 

17 

18 

19 

21 

28 

9 

iy2x3 

4.50 

4 

6 

7 

11 

13 

15 

20 

21 

23 

24 

33 

10 

2     x3 

6.00 

6 

8 

9 

15 

18 

21 

27 

28 

30 

33 

44 

11 

2     x4 

8.00 

8 

10 

12 

19 

23 

27 

35 

37 

39 

42 

57 

12 

2     x6 

12.00 

12 

15 

18 

29 

35 

40 

53 

56 

59 

64 

86 

NOTE. —  Table  based  on 
maximum  capacity. 


wires  filling  trunking   to   75   per  cent,   of  its 


TABLE   FOR   DETERMINING   REQUIRED   SIZE   OF   CONDUIT 


CONDUIT 

RUBBEB-COVERED   COPPER   WIRE.     R.  S.  A.  SPECIFICATIONS 

Inside 
Diam. 

Area 
Inside 

No. 
0 

1 

No. 

1 

1 

No. 
2 

No. 
4 

No. 
6 

2 

No. 
8 

No. 
9 

No. 
10 

No. 
12 

No. 
14 

No. 
16 

Inch 

Sq.  In. 

1 

.785 

1 

2 

2 

3 

3 

4 

4 

5 

iya 

1.77 

2 

2 

2 

4 

5 

5 

7 

8 

8 

9 

12 

2 

3.14 

3 

3 

4 

7 

8 

10 

12 

13 

14 

15 

21 

2y2 

4.91 

4 

5 

7 

11 

13 

15 

20 

21 

22 

24 

32 

3 

7.07 

6 

8 

10 

16 

19 

22 

28 

30 

32 

35 

47 

3% 

9.62 

9 

11 

13 

21 

26 

30 

38 

41 

43 

47 

63 

4 

12.57 

11 

14 

18 

28 

34 

39 

50 

54 

56 

62 

83 

. —  Table   based   on   wires  filling   conduit  to  75  per   cent,  of  its 
maximum  capacity. 


ELECTRIC  INTERLOCKING  HANDBOOK 


315 


JT  V> 


5i3e  1 
j>  Capping    250'  BM 

Capping    417' BM          T™Ki"9  MO'BM 
Trunking  1000'BM 


Capping   417 'BM 
TrunKing  667 'BM 


-4.- 
5*364 
Capping    417 'BM 
Trunking  1000'BM 


Capping    417 'BM 
Trunking  JOOO'BM 


Capping    500  BM 
TrunKing  10001  BM 


Capping   500'  BM 
Trunking  1000' BM 


Capping   333' BM 
TTunkmg  6S7'BM 


Capping   750'BM 
TrunKing  1500'  BM 


5136  10 

Capping  750'  BM 
TrunKing  2000'  BM 


E 


?V 


7" . 

5136  11 
Capping   675'  BM 
TrunKing  lbfe7'BM 


Copping    1667 'BM 
TrunKing          ' 


Fia.  270.    TBUNKING  SECTIONS 


Dimensions  as  shown  are  for  rough  sawed  trunking  and  capping  before 
surfacing.  To  determine  finished  dimensions  deduct  one-eighth  inch  from 
each  side  to  be  surfaced.  Amounts  of  board  feet  are  for  1,000  hneal  feet. 


316  GENERAL  RAILWAY  SIGNAL  COMPANY 


JUNCTION    BOX 
Fio.  271.     TRUNKING  AND  JUNCTION  Box  CONSTRUCTION 


ELECTRIC   INTERLOCKING   HANDBOOK 


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trunking,  .  . 

bio 

'a 
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318 


GENERAL  RAILWAY  SIGNAL  COMPANY 


FIG.  272.     G.  R.  S.  SPLIT  ELBOW  FOR  CONDUIT 


DIMENSIONS  OF  SPLIT  ELBOW 


Size 
Conduit 

DIMENSIONS 

A 

B 

C 

Inch 

Inch 

Inch 

Inch 

2 

2^6 

2tte 

2% 

2y2 

210/32 

2i%8 

Sfe 

3 

3%B 

3%a 

3% 

SECTION  XIV 


PORTLAND    CEMENT   CONCRETE 


COVERING    DESCRIPTION    OF    CLASSES 
OF   CONCRETE,   METHODS    OF    MIXING, 
AND    TABLES    OF   VOLUMES   OF   MATE- 
RIALS  REQUIRED 


PORTLAND    CEMENT    CONCRETE 
STORING 

IN  storing  cement,  wooden  blocks  should  be  placed  on  the 
floor  and  covered  with  boards ;  the  bags  of  cement  should  be 
piled  on  this  to  a  depth  of  six  or  eight  layers,  keeping 
the  piles  six  or  eight  inches  away  from  the  walls  of  the 
building  so  as  to  obtain  a  free  circulation  of  air  on  all  sides. 
The  cement  should  be  covered  with  canvas  or  roofing  paper. 

The  place  chosen  for  storing  the  cement  should  be  as  dry  as 
possible,  as  cement  absorbs  moisture  from  the  atmosphere 
with  great  readiness,  soon  becoming  lumpy  or  even  a  solid 
mass  if  the  storehouse  is  at  all  damp.  In  this  condition  it  is 
useless  and  should  be  thrown  away.  Lumps  caused  by 
pressure  while  being  stored  must  not  be  mistaken  for  cement 
that  has  been  wet  and  has  then  hardened;  lumps  caused  by 
pressure  are  easily  broken,  the  cement  being  perfectly  good. 

Portland  cement  is  shipped  in  paper  bags  or  cloth  sacks, 
the  second  means  being  recommended  as  best  for  the  average 
user. 

PROPORTIONS  OP  MATERIALS  FOR  CONCRETE 

A  Rich  Mixture,  with  proportions  of  1  :  1%  :  3,  is  used  for 
columns  or  other  structural  parts  subjected  to  high  stresses 
or  requiring  exceptional  water-tightness. 

A  Standard  Mixture,  with  proportions  of  1  :  2  :  4,  is  used  for 
reinforced  floors,  beams,  and  columns,  for  arches,  for  rein- 
forced engine  or  machine  foundations  subject  to  vibrations, 
for  tanks,  sewers,  conduits  and  other  water-tight  work. 

A  Medium  Mixture,  with  proportions  of  1  :  2%  :  5,  is  used  for 
ordinary  machine  foundations,  retaining  walls,  abutments, 
piers,  thin  foundation  walls,  building  walls,  ordinary  floors, 
sidewalks  and  sewers  with  heavy  walls. 

A  Lean  Mixture,  with  proportions  of  1  :  3  :  6  and  1  :  4  :  8,  is 
used  for  unimportant  work  in  masses,  for  heavy  walls,  for 
large  foundations  supporting  a  stationary  load  and  for  stone 
masonry  backing. 

CONSISTENCY  OF  CONCRETE 

A  Medium  or  Quaking  Mixture,  of  a  tenacious,  jelly-like  con- 
sistency which  quakes  on  ramming,  shall  be  used  for  ordinary 
mass  concrete,  such  as  foundations,  heavy  walls,  large  arches, 
piers  and  abutments. 

A  Wet  or  Mushy  Concrete,  so  soft  that  it  will  not  require 
ramming,  shall  be  used  for  rubble  concrete,  and  for  reinforced 
concrete,  such  as  thin  building  walls,  columns,  doors,  con- 
duits and  tanks. 

A  Dry  Concrete,  of  the  consistency  of  damp  earth,  may  be 
employed  in  damp  locations  for  mass  foundations,  which  must 
stand  severe  compressive  strain  within  one  month  after  placing, 
providing  it  is  spread  in  six  inch  layers  and  rammed 


322  GENERAL  RAILWAY  SIGNAL  COMPANY 


until  water  flushes  to  the  surface.     Dry  mixed  concrete  shall 
never  be  employed  with  steel  reinforcement. 

MIXING  CONCRETE  BY  HAND 

For  mixing  concrete  by  hand,  a  water-tight  platform  is 
recommended  on  which  is  first  spread  the  sand  and  then  the 
required  amount  of  cement.  Two  or  more  laborers,  an 
even  number  working  on  each  side  of  the  board,  should  syste- 
matically turn  the  cement  into  the  sand  with  a  slight  "flip" 
on  leaving  the  shovel,  being  sure  to  cut  to  the  bottom  of  the 
pile  at  each  stroke.  This  operation  will  have  moved  the  loca- 
tion of  the  pile  about  two  feet.  Reversing  the  direction  of 
the  operation  brings  the  pile  to  its  original  position,  but  in  a 
mixed  condition.  By  cutting  into  the  pile  with  a  shovel,  an 
idea  of  the  uniformity  of  mixing  can  easily  be  obtained;  the 
appearance  of  streaks  indicates  the  need  for  another  turning. 
If  the  mixture  is  of  uniform  color,  the  required  amount  of 
stone  may  be  distributed  over  the  pile,  which  should  be  turned 
in  the  same  manner  until  thoroughly  mixed.  Water  is  then 
added  and  the  mass  again  turned  until  the  desired  consistency 
is  secured. 

MIXING  CONCRETE  BY  MACHINE 

Recent  experiments  conducted  on  the  strength  of  machine 
concrete  mixed  for  varying  periods  indicate  that  the  materials 
must  remain  in  agitation  with  the  water  for  at  least  a  full 
minute.  The  tendency  to  rush  work  is  not  productive  of  good 
concrete,  and  should,  consequently,  be  curbed.  In  general, 
machine  mixing  where  carefully  controlled  is  superior  to  hand 
work,  since  fatigue  of  the  workman  has  no  influence  upon  the 
thoroughness  of  mixing. 

CAUTIONS 

On  adding  water  to  the  dry  cement  it  becomes  a  soft,  sticky 
paste,  and  will  remain  so  for  about  one-half  hour,  after 
which  it  begins  to  harden  or  "set."  To  disturb  the  concrete 
after  this  initial  set  has  started  means  a  decided  loss  in  strength, 
while  to  disturb  it  after  the  set  is  well  under  way  means  to 
destroy  the  concrete.  It  should,  therefore,  be  remembered 
that  Portland  cement  concrete  must  be  placed  in  position 
within  twenty  or  thirty  minutes  from  the  time  after  it  is 
first  wet. 

A  green  cement  mixture,  which  can  be  easily  frozen  at  a 
temperature  below  32  degrees  Fahr.,  should  be  protected 
from  exposure  by  placing  canvas  or  roofing  paper  over  the 
form  and  covering  this  with  four  or  five  inches  of  earth  or 
straw.  Freezing  does  not  materially  affect  the  binding  qualities 
of  good  Portland  cement,  provided  the  concrete  is  not  sub- 
jected to  alternate  freezing  and  thawing,  does  not  freeze 
until  after  placing,  and  is  not  subjected  to  any  load  until 
it  has  been  thawed  out  and  allowed  to  "set"  in  the  usual 


ELECTRIC  INTERLOCKING   HANDBOOK 


323 


way.  It  is  safest  to  avoid  mixing  on  days  when  the  tem- 
perature is  below  the  freezing  point,  that  is  32  degrees 
Fahr.  If  it  is  necessary,  however,  to  make  concrete  under 
these  conditions,  the  sand,  water  and  stone  should  be  heated, 
and  if  the  cold  is  severe,  salt  should  be  added  in  proportions  of 
two  pounds  to  each  cubic  yard  of  concrete. 

EDITOR'S   NOTE 

Above  article  based  on  data  furnished  by  Universal  Portland 
Cement  Company. 


FIG.  273.     MEASURING  Box 


DIMENSIONS   OF   MEASURING   BOXES   FOR   TWO   BAG 
BATCH   OF   CONCRETE 


PROPORTIONS 

SIZE  OF  MEASURING  Box 

Sand 

Stone  or  Gravel 

Cement 
(2  bags) 

Sand 

or 

A 

B 

C 

A 

B       |       C 

Ft.  In. 

Ft.  In. 

In. 

Ft.  In. 

Ft.  In. 

In. 

1 

Itt 

3 

3-0 

2-0 

6 

3-0 

2-0 

12 

1 

2 

3 

4-0 

2-0 

6 

3-0 

2-0 

12 

1 

2 

4 

4-0 

2-0 

6 

4-0 

2-0 

12 

1 

2y2 

4 

4-0 

2-6 

6 

4-0 

2-0 

12 

1 

2V2 

5 

4-0 

2-6 

6 

4-0 

2-6 

12 

1 

3 

5 

4-0 

3-0 

6 

4-0 

2-6 

12 

1 

3 

6 

4-0 

3-0 

6 

4-0 

3-0 

12 

324 


GENERAL  RAILWAY  SIGNAL  COMPANY 


VOLUME    OF   COMPACTED    STONE    OR   GRAVEL   CONCRETE 
PER   SACK    OF   CEMENT 


PROPORTIONS 

QUANTITIES 

Cement 

Sand 

Gravel  or 
Stone 

Cement 
Sacks 

Sand 

Gravel  or 
Stone 

Concrete 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft 

1 

1% 

3 

1 

1.5 

3.0 

3.52 

1 

2 

3 

1 

2.0 

3.0 

3.90 

1 

2 

4 

1 

2.0 

4.0 

4.48 

1 

2% 

4 

1 

2.5 

4.0 

4.85 

1 

2V2 

5 

1 

2.5 

5.0 

5.45 

1 

3 

5 

1 

3.0 

5.0 

5.80 

1 

3 

6 

1 

3.0 

6.0 

6.40 

MATERIALS    REQUIRED   FOR   ONE    CUBIC    YARD   OF 
COMPACTED    STONE    OR   GRAVEL   CONCRETE 


PROPORTIONS 

QUANTITIES 

Cement 

Sand 

Stone  or 
Gravel 

Cement 

Sand 

Stone  or  Gravel 

Sacks 

Cu.  Ft. 

Cu.  Yds. 

Cu.  Ft. 

Cu.  Yds. 

1 

1% 

3 

7.64 

11.5 

.43 

23.0 

.85 

1 

2 

3 

6.96 

13.9 

.51 

20.9 

.77 

1 

2 

4 

6.04 

12.1 

.45 

24.2 

.90 

1 

2% 

4 

5.56 

13.9 

.51 

22.2 

.82 

1 

2% 

5 

4.96 

12.4 

.46 

24.8 

.92 

1 

3 

5 

4.64 

13.9 

.51 

23.2 

.86 

1 

3 

6 

4.24 

12.7 

.47 

25.4 

.94 

Stone  and  gravel  considered  as  having  45  per  cent,  voids. 
Tables  based  on  1  sack  cement  =:!  cubic  foot. 
4  sacks  cement  =  1  barrel. 

Above  quantities  may  vary    10   per  cent,   in  either  direction,  depend- 
ing upon  the  materials  used  and  the  compactness  of  the  concrete. 

Data  for  above  tables  from  the  Universal  Portland  Cement  Company. 


ELECTRIC   INTERLOCKING   HANDBOOK  325 

R.  S.  A.  SPECIFICATIONS  FOR  PORTLAND  CEMENT 
CONCRETE  (1912) 

1.  GENERAL 

These  specifications  are  for  making  concrete  as  used  in 
signal  construction. 

2.  CEMENT 

Cement  shall  be  Portland,  either  American  or  Foreign, 

which  will  meet  the  requirements  of  the 

specifications. 

3.  SAND 

Sand  shall  be  clean,  sharp,  coarse,  and  of  grains  varying 
in  size.  It  shall  be  free  from  sticks  and  other  foreign 
matter,  but  it  may  contain  clay  or  loam  not  to  exceed  five 
(5)  per  cent.  Crusher  dust,  screened  to  reject  all  particles 
over  one-fourth  (^4)  inch  in  diameter,  may  be  used  instead 
of  sand,  if  approved  by  the  Engineer. 

4.  STONE 

Stone  shall  be  sound,  hard,  and  durable,  crushed  to  sizes 
not  exceeding  two  (2)  inches  in  any  direction.  For  rein- 
forced concrete,  sizes  usually  are  not  to  exceed  three- 
fourths  (%)  inch  in  any  direction,  but  may  be  varied  to 
suit  character  of  reinforcing  material. 

5.  GRAVEL 

Gravel  shall  be  composed  of  clean  pebbles  of  hard  and 
durable  stone  of  sizes  not  exceeding  two  (2)  inches  in 
diameter  and  shall  be  free  from  clay  and  other  impurities 
except  sand.  When  containing  sand  in  any  considerable 
quantity,  the  amount  of  sand  per  unit  of  volume  of  gravel 
shall  be  determined  accurately,  to  admit  of  the  proper 
proportion  of  sand  being  maintained  in-  the  concrete 
mixture. 

6.  WATER 

Water  shall  be  clean  and  reasonably  clear,  free  from 
sulphuric  acid  or  strong  alkalies. 

7.  MEASURE 

The  unit  of  measure  shall  be  the  barrel,  which  shall  be 
taken  as  containing  three  and  eight-tenths  (3.8)  cu.  ft. 
Four  (4)  bags  containing  ninety-four  (94)  pounds  of 
cement  each  shall  be  considered  the  equivalent  of  one  (1) 
barrel.  Fine  and  coarse  aggregates  shall  be  measured 
separately  as  loosely  thrown  into  the  measuring  receptacle. 


326  GENERAL  RAILWAY  SIGNAL  COMPANY 


8.  DENSITY  OF  INGREDIENTS 

(a)  For  pipe  carrier  foundations  and  reinforced  con- 
crete, a  density  proportion  based  on  1:6  is  recommended, 
i.  e.,  one  (1)  part  of  cement  to  a  total  of  six  (6)  parts  of 
fine  and  coarse  aggregates  measured  separately. 

(6)  For  signal  and  other  foundations  made  in  place  a 
density  proportion  based  on  1:9  is  recommended,  i.  e.,  one 
(1)  part  of  cement  to  a  total  of  nine  (9)  parts  of  fine  and 
coarse  aggregates  measured  separately. 

9.  MIXING 

(a)  Tight  platforms  shall  be  provided  of  sufficient  size 
to  accommodate  men  and  materials  for  progressive  and 
rapid  mixing.  Batches  shall  not  exceed  one  (1)  cu.  yd. 
and  smaller  batches  are  preferable. 

(6)  Spread  the  sand  evenly  upon  the  platform,  then  the 
cement  upon  the  sand,  and  mix  thoroughly  until  of  an 
even  color.  Add  all  the  water  necessary  to  make  a  thin 
mortar  and  spread  again;  add  the  gravel  if  used,  and 
finally  the  broken  stone,  both  of  which,  if  dry,  should  first 
be  thoroughly  wet  down.  Turn  the  mass  with  shovels  or 
hoes  until  thoroughly  incorporated,  and  all  the  gravel  and 
stone  is  covered  with  mortar;  this  will  probably  require 
the  mass  to  be  turned  four  (4)  times. 

(c)  Another  approved  method,  which  may  be  permitted 
at  the  option  of  the  Engineer  in  charge,  is  to  spread  the 
sand,  then  the  cement  and  mix  dry,  then  the  gravel  or 
broken  stone.     Add  water  and  mix  thoroughly  as  above. 

(d)  A  machine  mixer  may  be  used  whenever  the  volume 
of  work  will  justify  the  expense  of  installing  the  plant. 
The  necessary  requirements  for  the  machine  will  be  that 
a  precise  and  regular  proportioning  of  materials  can  be 
controlled  and  that  the  product  delivered  shall  be  of  the 
required  consistency  and  thoroughy  mixed. 

10.  CONSISTENCY 

The  concrete  will  be  of  such  consistency  that  when 
dumped  in  place  it  will  not  require  much  tamping.  It 
shall  be  spaded  down  and  tamped  sufficiently  to  level  off, 
and  the  water  should  rise  freely  to  the  surface. 

11.  FORMS 

(a)  Where  necessary,  forms  shall  be  well  built,  substan- 
tial and  unyielding,  properly  braced,  or  tied  together  by 
means  of  wire  or  rods,  and  shall  conform  to  lines  given. 

(b)  For  all  important  work,  the  lumber  used  for  face 
work  shall  be  dressed  on  one  (1)  side  and  both  edges  to  a 
uniform  thickness  and  width,  and  shall  be  sound  and  free 
from  loose  knots,  secured  to  the  studding  or  uprights  in 
horizontal  lines. 


ELECTRIC  INTERLOCKING  HANDBOOK  327 


(c)  For  backings  and  other  rough  work  undressed  lum- 
ber may  be  used. 

(d)  Where  corners  of  the  masonry  and  other  projections, 
liable  to  injury,  occur,  suitable  moldings  shall  be  placed 
in  the  angles  of  the  forms  to  round  or  bevel  them  off. 

(e)  Lumber  once  used  in  forms  shall  be  cleaned  before 
being  used  again. 

(/)  The  forms  must  not  be  removed  within  thirty-six 
(36)  hours  after  all  the  concrete  in  that  section  has  been 
placed.  In  freezing  weather  they  must  remain  until  the 
concrete  has  had  a  sufficient  time  to  become  thoroughly 
hardened. 

(g)  In  dry,  but  not  freezing,  weather  the  forms  shall  be 
drenched  with  water  before  the  concrete  is  placed  against 
them. 

12.  DISPOSITION 

(a)  Each  layer  shall  be  left  somewhat  rough  to  insure 
bonding  with  the  next  layer  above;  and  if  it  be  already 
set,  shall  be  thoroughly  cleaned  and  scrubbed  with  coarse 
brushes  and  water  before  the  next  layer  is  placed  upon  it. 

(&)  Concrete  shall  be  deposited  in  the  molds  in  layers  of 
uniform  thickness  throughout. 

(c)  The  work  shall  be  carried  up  in  sections  of  convenient 
length  and  each  section  completed  without  intermission. 

(d)  In  no  case  shall  work  on  a  section  stop  within  eight- 
een (18)  inches  of  the  top. 

(e)  Concrete  shall  be  placed  immediately  after  mixing 
and  any  having  an  initial  set  shall  be  rejected. 

13.  FACING 

(a)  The  facing  will  be  made  by  carefully  working  the 
coarse  material  back  from  the  form  by  means  of  a  shovel 
bar  or  similar  tool,  so  as  to  bring  the  excess  mortar  of  the 
concrete  to  the  face. 

(6)  About  one  (1)  inch  of  mortar  (not  grout)  of  the 
same  proportions  as  used  in  the  concrete  may  be  placed 
next  to  the  forms  immediately  in  advance  of  the  concrete. 

(c)  Care  must  be  taken  to  remove  from  the  inside  of  the 
forms  any  dry  mortar,  in  order  to  secure  a  perfect  face. 

14.  FINISHING 

(a)  After  the  forms  are  removed,  which  should  generally 
be  as  soon  as  possible  after  the  concrete  is  sufficiently 
hardened,  any  small  cavities  or  openings  in  the  face  shall 
then  be  neatly  filled  with  mortar.  The  entire  face  shall 
then  be  washed  with  a  thin  grout  of  the  consistency  of 
whitewash,  mixed  in  the  same  proportion  as  the  mortar 
of  the  concrete.  The  wash  shall  be  applied  with  a  brush. 
The  earlier  the  above  operations  are  performed  the  better 
will  be  the  result. 


328  GENERAL  RAILWAY  SIGNAL  COMPANY 

(6)  The  top  surface  of  all  crank,  compensator,  well  hole, 
lock,  dwarf,  and  high  signal  foundations  shall  be  rubbed 
smooth  by  hand  and  shall  be  true  to  grade  and  line. 

15.  WATERPROOFING 

Where  waterproofing  is  required,  a  thin  coat  of  mortar 
or  grout  shall  be  applied  for  a  finishing  coat  upon  which 
shall  be  placed  a  covering  of  suitable  waterproofing  mate- 
rial. 

16.  FREEZING  WEATHER 

Concrete  to  be  left  above  the  surface  of  the  ground  shall 
not  be  constructed  in  freezing  weather,  except  by  special 
instructions.  In  this  case  the  sand,  water  and  broken 
stone  shall  be  heated,  and  in  severe  cold,  salt  shall  be  added 
in  proportion  of  about  two  (2)  pounds  per  cu.  yd. 

17.  REINFORCED  CONCRETE 

Where  concrete  is  deposited  in  connection  with  metal 
reinforcing,  the  greatest  care  must  be  taken  to  insure  the 
coating  of  the  metal  with  mortar,  and  the  thorough  com- 
pacting of  the  concrete  around  the  metal.  Whenever  it 
is  practicable  the  metal  shall  be  placed  in  position  first. 
This  can  usually  be  done  in  the  case  where  the  metal 
occurs  in  the  bottoms  of  the  forms,  by  supporting  the 
metal  on  transverse  wires,  or  otherwise,  and  then  flushing 
the  bottoms  of  the  forms  with  cement  mortar,  so  as  to  get 
the  mortar  under  the  metal,  and  depositing  the  concrete 
immediately  afterward.  The  mortar  for  flushing  the  bars 
shall  be  composed  of  one  (1)  part  cement  and  two  (2)  parts 
sand.  The  metal  used  in  the  concrete  shall  be  free  from 
dirt,  oil,  or  grease.  All  mill  scale  shall  be  removed,  by 
hammering  the  metal,  or  preferably  by  pickling  the  same 
in  a  weak  solution  of  muriatic  acid.  No  salt  shall  be  used 
in  reinforced  concrete  when  laid  in  freezing  weather. 


SECTION  XV 


WRITTEN    CIRCUITS 


INCLUDING  NOMENCLATURE  OF  OPER- 
ATED   UNITS,    CIRCUITS,    AND    WIRES, 
WITH  TYPICAL   ILLUSTRATIONS 


WRITTEN  CIRCUITS 

WRITTEN  Circuits,  as  hereafter  described,  have  been  de- 
signed to  overcome  the  faults  in  the  old  method  of 
circuit  drawing  which  developed  upon  attempting  its 
application  to  large  interlocking  installations. 

A  circuit  plan  for  an  interlocking,  drawn  up  by  the  old 
method,  consisted  of  a  track  plan,  more  or  less  to  scale,  on 
which  plan  symbols  of  the  various  pieces  of  apparatus  were 
shown,  placed  as  far  as  possible  in  their  proper  relative  posi- 
tions; such  points  as  should  be  electrically  connected  were 
joined  by  lines  representing  wires. 

While  this  method  has  been  of  great  value  in  the  past  and 
still  remains  so  for  typical  circuits,  automatic  signal  work  and 
small  interlocking  plants,  the  plans  run  into  such  size  when 
used  for  large  interlocking  installations  as  to  practically 
prohibit  its  use  in  connection  with  that  class  of  work. 

It  is  true,  furthermore,  that  a  great  deal  of  unnecessary 
labor  is  involved  in  both  drawing  and  deciphering  the  circuits. 
For  example:  The  engineer  in  drawing  up  such  a  plan  begins 
with  some  simple  sketches,  perhaps  using  symbols  of  his  own 
invention.  After  carefully  checking  these  circuits  and  assur- 
ing himself  of  their  correctness,  he  converts  them  into  the 
rather  elaborate  form  described  above,  in  which  the  attempt 
to  keep  down  the  size  of  the  plan  is  very  apt  to  result  in  a 
cramped  arrangement  of  apparatus  and  a  tangle  of  wires. 
When  the  man  on  maintenance  or  installation  wishes  to  make 
use  of  these  circuits,  he  has  to  reverse  the  process  and  reduce 
the  composite  drawing  to  its  simple  elements. 

Written  circuits  have  been  designed  to  eliminate  this  un- 
necessary work  and  especially  to  secure  plans  in  which  the 
complete  circuit  for  any  given  switch,  signal,  or  other  function, 
can  be  written  on  a  page  of  ordinary  size  without  crowding, 
these  pages  being  bound  together  in  a  book  which  will  easily 
and  instantly  permit  reference  to  be  made  to  any  portion  of 
the  wiring  of  the  plant. 

A  set  of  plans  drawn  up  in  accordance  with  this  method 
involves  the  following : 

1.  Location  Plan.     This   shows   the   relative   location   of 
track,  interlocking  station,  switch  and  signal  functions,  track 
relays,  switch  circuit  controllers,  etc.     Notes,  such  as  for  the 
routing  of  signal  arms,  should  be  included  on  this  plan. 

2.  Typical  Plan  of  Special  Circuits.     This  shows  what  is 
proposed  to  be  accomplished   in   route   locking,  etc.,   these 
circuits  to  be  drawn  up  either  by  the  old  method,  or  in  "written" 
form,  as  desired. 

3.  Typical  Plans  of  Signal  Circuits,  Switch  Circuits,  etc. 

4.  Special  Circuits,  made  up  in  "written"  form.     These 
special  circuits  are  separated  so  that  circuits  not  connected 
together  are  kept  entirely  apart  from  each  other,  being  drawn 


332  GENERAL  RAILWAY  SIGNAL  COMPANY 


up  on  separate  sheets.  This  desirable  feature  causes  the 
"written"  circuits  to  be  exceptionally  clear  and  permits  their 
being  readily  grasped. 

5.  Detail  Wiring  Plans.  It  may  be  helpful  under  certain 
conditions  to  add  to  the  circuits  listed  above,  detail  plans 
showing  the  wiring  for  the  indicator  group  and  interlocking 
machine. 

In  drawing  up  such  circuits  it  is  necessary  to  use  a  nomen- 
clature for  naming  the  apparatus  and  to  adopt  symbols  to  be 
used  in  writing  the  circuits.  A  nomenclature  of  operated  units 
and  of  circuits,  which  has  been  used  for  some  time  by  the 
General  Railway  Signal  Company  and  found  thoroughly 
practicable  is  given  on  the  following  pages. 

On  page  337  is  given  a  nomenclature  of  wires.  It  is  to  be 
understood  that  this  is  equally  applicable  to  written  circuits 
or  to  circuits  drawn  up  by  the  older  methods. 


NOMENCLATURE  OF  OPERATED  UNITS 

A  —  Approach  Relay  or  Indicator.  With  number  as  pre- 
fix, indicating  number  of  principal  signal  up  to  which  the 
approach  section  controlling  same  leads,  as  10A. 

B  —  Positive  Battery  Wire.  Used  alone  where  only  one 
battery  voltage  is  in  use.  When  used  with  H  as  a 
suffix  (BH)  indicates  110  volt  battery.  When  used  with 
L  as  a  suffix  (BL)  indicates  low  voltage  battery.  When 
more  than  one  low  voltage  battery  is  used  with  dif- 
ferent voltage,  use  number  indicating  voltage  as  further 
suffix,  as  BL-10,  indicating  10  volt  battery. 

C  —  Common  Wire.  Used  alone  when  only  one  common  is 
in  use.  When  used  with  H  as  a  suffix  (CH)  indicates 
110  volt  common.  When  used  with  L  as  a  suffix  (CL) 
indicates  low  voltage  common.  When  more  than  one 
high  voltage  or  low  voltage  common  is  used,  use  num- 
bers as  further  suffixes.  (CH-1,  CH-2,  CL-1,  etc.) 

D  —  Relay  or  Indicator  Controlling  the  Ninety  Degree  Posi- 
tion or  Distant  Function  of  a  Signal.  With  prefix  indi- 
cating the  number  of  principal  signal  which  it  controls, 
as  10D,  indicating  relay  or  indicator  controlling  the 
ninety  degree  position  of  signal  No.  10,  or  signal  No. 
10  if  it  is  a  distant  signal  in  two  position  signaling. 

E  —  Special  Relay  or  Indicator  (other  than  T,  D,  H,  K,  or  F 
relays  and  indicators).  With  number  as  prefix  indi- 
cating number  of  principal  unit  entering  into  its  control, 
or  indicating  principal  unit  which  it  controls. 

F  —  Relay  or  Indicator  Repeating  a  Track  Relay  or  Signal. 
With  number  as  a  prefix  indicating  number  of  relay  or 
signal  which  it  repeats,  as  10F. 
FP  —  Floor  Push. 


ELECTRIC  INTERLOCKING  HANDBOOK  333 


G  —  Switch  Indicator.  With  number  of  signal  governing 
through  block  in  which  switch  is  located  as  prefix,  as  10G. 
H  —  Relay  or  Indicator  Controlling  Forty-five  Degree  Position 
or  Home  Function  of  a  Signal.  With  prefix  indicating  the 
number  of  principal  signal  which  it  controls,  as  10H,  indi- 
cating relay  or  indicator  controlling  the  forty-five  degree 
position  of  signal  No.  10,  or  signal  No.  10  if  it  is  a  home 
signal  in  two  position  signaling. 

J  —  Junction  Box  or  Terminal  Board.  With  arbitrary  num- 
ber as  prefix,  as  10J. 

K  —  Lock  Relay.     Used  in  connection  with  route  or  detector 
locking  for   interrupting   the   current   supply  to  switch 
and    derail    machines,  etc.,  with    number    as    a    prefix, 
indicating  track  section  affected  by  it,  as  10K. 
KS  —  Knife  Switch. 
L  —  Lever  Lock.     With  prefix  indicating  number  of  lever 

which  it  locks,  as  10L,  meaning  lock  on  lever  No.  10. 
LA  —  Lightning  Arrester. 
LC  —  Latch  Contact.     With  prefix  indicating  number  of  lever, 

as  10LC. 

M  —  Man-hole.     With  arbitrary  number  as  prefix,  as  10M. 
PB  —  Push  Button  or  Strap  Key. 

PC  —  Pole  Changing  Relay.  With  prefix  indicating  number 
of  signal  at  which  relay  is  located  or  number  of  signal 
controlled  by  it. 

S  —  Stick  Relay.  Used  in  connection  with  route  locking. 
With  number  as  prefix,  as  10S,  meaning  stick  relay 
locking  route  of  signal  No.  10,  or  locking  operated  units 
in  track  section  10T,  if  separate  stick  relays  are  used 
for  each  track  section. 

SL  —  Outlying  Switch  Lock.  With  number  as  prefix  indi- 
cating number  of  controlling  lever.  Use  arbitrary 
number  if  there  is  no  controlling  lever. 

T  —  Track  Circuit.  With  number  as  prefix  indicating  num- 
ber of  track  circuit,  as  10T,  which  is  also  the  name  of 
the  track  relay  for  track  circuit  10T. 

NOTE. —  The  number  for  the  track  circuit  is  taken  from  the  following  in 
the  order  given : 

M.  P.  Frog  or 

Switch  or 

Derail  or 

Arbitrary  numbers  01,  02,  03,  etc. 

TL  —  Traffic  Lock.    With  prefix  indicating  number  of  lever 

which  it  controls,  as  10TL. 
TP  —  Telephone. 
TR  —  Time    Release.     With    number    as    prefix    indicating 

principal  unit  which  it  releases,  as  10TR. 
V  —  Electric  Slot.     With  number  of  signal  as  prefix,  as  10V. 
XB  —  Crossing  Bell     With  arbitrary  number  as  prefix,  such 

as  10XB. 


334 


GENERAL  RAILWAY  SIGNAL  COMPANY 


NOMENCLATURE   OF  CIRCUITS 
SYMBOLS  FOR  OPERATED  UNITS 

An  operated  unit  (signal,  relay,  indicator,  etc.)  is  repre- 
sented by  a  rectangle  with  the  number  and  letter  of  the  relay, 
signal,  etc.,  inside,  thus: 


The  forty-five  degree  mechanism  of  a  three-position  signal 
is  indicated  thus : 


And  the  ninety  degree  thus : 


CIRCUIT  CONTROLLERS  OPERATED  BY  SWITCH  POINTS 
Closed  when  switch  is  normal,.     . 


Closed  when  switch  is  reversed,  .    .    . 

Closed   when   switch  is  normal   and 
locked  in  position, 

Closed  when  switch  is  reversed  and 
locked  in  position, 


/-Switch  Number 
1O 


CIRCUIT  CONTROLLERS  OPERATED  BY  SIGNALS 

'_ jnal  Number 

Closed  at    0°  only, 

Closed  at  45°  only, 

Closed  at  90°  only, 

Closed  at  60°  only, 

Closed  between    0°  and  45°,    .... 

Closed  between  45°  and  90°,  etc.,   .    . 


10 


45-9O 


ELECTRIC   INTERLOCKING  HANDBOOK 


335 


CIRCUIT  CONTROLLERS  OPERATED  BY  LEVERS 

N  B   C  D  R    Symbol 


N — Full  normal  position  of  lever. 
B — Normal  indication  position. 
C  — Intermediate  position. 
D — Reverse  indication  position. 
R — Full  reverse  position. 

Heavy  horizontal  line  indicates  portion 
of  cycle  of  lever  through  which  circuit  is 
closed . 


RELAY  AND  INDICATOR  CONTACTS 

Neutral  front  contact, 

Neutral  back  contact, 

Normal  polarized  contact 


Reverse  polarized  contact, 

Intermediate  contact  on  three-posi- 
tion relay:  Closed  when  relay  is 
deenergized, 


TIME  RELEASE  CONTACT 

Normally  closed, 

Normally  open, 


Relay  Number 


1OT 
JO_T 
1O  T 

tor 

10  T 


336  GENERAL  RAILWAY  SIGNAL  COMPANY 

LATCH  CONTACT 
Normally  closed, 

Normally  open, 

PUSH  BUTTON  OR  STRAP  KEY 
Normally  closed, 

Normally  open, P  B 

KNIFE  SWITCH 
Normally  closed, 


Normally  open, K  s 

TERMINAL  IQJ  Meaning  terminal  in  junction  box 

No.  10  or  on  terminal  board  No. 
10. 

NOTE. —  Small  numbers  written  as  exponents  to  the  right  and  above 
relay  numbers,  lever  numbers,  etc.,  indicate  contact  numbers. 

Relay  or  indicators  contacts  are  numbered  from  left  to  right  looking 
toward  the  relay. 

GRAPHICAL  SYMBOLS  FOR  CIRCUIT  CONTROLLERS 
OPERATED  BY  LEVERS 

Model  2,  interlocking  "machine. 


LEVER  CONTACT  NUMBERING 

Model  2,  interlocking  machine. 

BOTTOM  TOP 

1357 


M  y  M 

W  W  M  M 


REVERSE 
NORMAL 


ELECTRIC   INTERLOCKING   HANDBOOK  337 


NOMENCLATURE   OF  WIRES 

The  matter  of  primary  importance  in  naming  wires  is  to 
have  a  different  name  for  each  wire  and  have  it  so  shown  on 
both  the  plan  and  suitable  tags  attached  to  the  wires:  this  in 
order  that  a  wire  on  the  ground  may  be  quickly  identified  on 
the  plan. 

At  the  same  time  it  is  highly  desirable  to  have  a  wire  nomen- 
clature system  that  is  suggestive,  so  as  to  reduce,  as  far  as 
possible,  the  necessity  for  reference  to  plans. 

On  account  of  the  multitude  of  circuit  combinations  possible, 
a  system  must  be  rather  elastic.  With  all  of  the  above  taken 
into  consideration,  the  following  is  submitted  as  a  practical 
system  of  wire  nomenclature. 

NOTE. —  Names  of  wires  are  shown  on  plans  in  brackets,  thus:    (10D). 
Number  of  cable  containing  a  wire  may  be  written  above  and  at  right 
angles  to  the  wire,  thus :  o 

I  —  Indication  Wire.     With  number  of  unit  which  it  indi- 
cates as  prefix,  as  101. 
LL  —  Lighting  Wire. 
N  —  Normal  Control  Wire.     With  number  of  operated  unit 

which  it  controls  as  prefix,  as  ION. 
P  —  Ninety  Degree  Control  Wire.     With  number  of  signal  as 

prefix,  as  10P. 

R  —  Reverse  Control  Wire.  With  number  of  operated  unit 
which  it  controls  as  prefix,  as  10R.  If  10  is  a  three-position 
signal,  10R  is  the  name  of  the  forty-five  degree  control 
wire. 

V  —  Slot  Wire.    With  number  of  signal  as  prefix,  as  10V. 
X  —  Wire  going  to  positive  battery  through  a  circuit  con- 
troller on  a  signal  closed  in  the  zero  degree  position  only, 
with  the  number  of  the  signal  as  a  prefix,  as  10X. 
Y  —  Wire  going  to  positive  battery  through  a  circuit  con- 
troller on  a  signal  closed  from  zero  to  forty-five  degrees 
only,  with  the  number  of  the  signal  as  a  prefix,  as  10Y. 
Z  —  Wire  going  to  positive  battery  through  a  circuit  controller 
on  a  signal  closed  in  the  clear  position  if  the  signal  is  a 
two-position  signal,  or  closed  from  forty-five  to  ninety 
degrees  if  the  signal  is  a  three-position  signal,  with  the 
number  of  the  signal  as  a  prefix,  as  10Z. 
Wires  not  covered  by  the  above  are  named  as  follows : 
A  wire  leading  from  the  operating  coil  of  a  unit  toward 
battery  positive  takes  the  name  of  this  unit,  as  10H,  meaning 
the  wire  from  the  coil  of  home  control  relay  for  signal  No.  10 
leading  to  positive.     After  passing  through  a  circuit  controller, 
it  takes  the  number  "1"  as  a  suffix,  as  10H1.     This  suffix 
number  increases  by  one  as  the  wire  successively  breaks  through 
additional  controllers. 

The  wire  leading  from  the  operating  coil  to  battery  negative, 
takes  the  name  of  the  unit  with  the  letter  "C"  as  a  prefix,  as 


338 


GENERAL   RAILWAY  SIGNAL  COMPANY 


C10H,  and  after  breaking  through  successive  controllers  is 
written  C10H1,  C10H2,  etc. 

The  above  method  applies  directly  to  simple  circuits  having 
no  branches,  thus: 


In  cases  of  branch  wiring  this  method  is  applied  directly  to 
the  principal  circuit  —  circuit  for  superior  route.  The  first 
branch  from  this  circuit  takes  the  suffixes  21,  22,  etc.,  instead 
of  1,  2,  etc.  The  second  branch  41,  42,  etc.,  thus  continuing 
allowing  twenty  numbers  for  each  branch. 


^EEE 


!  a 


1000* 


1TR 


BL 


BH 


CH 


Fia.  274.     SECTION  OF  LOCATION  PLAN  WITH  SPECIAL  CIRCUITS 


ELECTRIC   INTERLOCKING   HANDBOOK 


339* 


ILLUSTRATIONS 

Illustrative  of  "Written  Circuits"  and  "Wire  Nomen- 
clature," is  shown  in  Fig.  274,  a  section  of  an  interlocking 
plant  with  the  special  circuits  used  in  connection  with  such  an 
arrangement.  In  accordance  with  the  instructions  given  under 
" Location  Plan"  on  page  331,  the  track  plan  with  the  rela- 
tive location  of  signal  and  switch  functions,  track  relays  and 
the  interlocking  station  with  its  indicators,  relays,  etc.,  is  shown. 

Below  the  track  plan  are  shown  the  special  circuits  drawn 
up  in  written  form.  Referring  to  the  sheets  of  nomenclature 
shown  on  the  preceding  pages,  it  will  be  seen  that  the  circuit 


uz 


L@ — i 


FIG.  275.     SIGNAL  SELECTING  CIRCUIT 


shown  at  the  top  is  for  the  control  of  the  annunciator  for 
signal  No.  1,  this  taking  low  voltage  battery  through  front 
contacts  of  the  track  relays  for  sections  03T  and  02T.  Sim- 
ilarly the  control  of  lock  1L  takes  battery  through  normally 
closed  contact  No.  2  of  screw  release  1TR,  the  front  point  of 
home  relay  3F,  the  front  point  of  contact  No.  2  of  stick  relay 
IS  and  the  latch  contact  of  the  lock  itself;  the  current  after 
passing  through  the  lock  goes  to  the  low  voltage  common 
wire.  Information  regarding  the  operation  of  this  type  of 
special  circuit  may  be  had  by  reference  to  the  Section  on 
''Electric  Locking  Circuits"  (page  133). 

f  Fig.  275  illustrates  the  method  of  writing  a  signal  selecting 
circuit.  This  is  included  principally  to  show  the  application  of 
the  wire  nomenclature  to  the  different  branches  of  the  same 
circuit.  The  wires  of  each  branch  are  designated  in  the  same 
manner  as  in  the  principal  circuit  but  with  the  suffixes  21,  22, 
23,  or  41,  42,  43,  etc.,  these  depending  upon  the  order  in  which 
the  different  branches  are  taken  from  the  principal  circuit. 


SECTION  XVI 


SIGNAL   ASPECTS   AND   SYMBOLS 


COVERING    STANDARDS    ADOPTED    BY 
THE    RAILWAY    SIGNAL    ASSOCIATION 


SIGNAL  ASPECTS  AND   SYMBOLS 

R.  S.  A.  PRINCIPLES   OF   SIGNAL    INDICATIONS 

(1906) 

(a)  On  all  high  signals  conferring  or  restricting  rights  a 
red  light  shall  be  the  night  indication  for  STOP.  A  yellow 
light  shall  be  the  night  indication  for  CAUTION,  and  a  green 
light  the  night  indication  for  PROCEED. 

NOTE. — The  word  caution  to  be  used  as  indicating  the  function  of 
a  distant  signal. 

(6)  The  day  indication  of  semaphore  signals  shall  be 
given  in  the  upper  right-hand  quadrant. 

(c)  The  semaphore  arm  in  the  horizontal  position  shall 
indicate  STOP,  inclined  upward  forty-five  (45)  degrees, 
CAUTION,  and  inclined  upward,  ninety  (90)  degrees, 

PROCEED. 

SIGNALING   PRACTICE  AS   DEFINED   BY  THE 

R.  S.  A.  (1913) 
MEMORANDUM  ON  THE  ESSENTIALS  OF  SIGNALING 

Incorporated  in  the  Report  of  the  Committee  on  Trans- 
portation of  the  American  Railway  Association,  May,  1911. 

"The  reports  of  various  Committees  of  the  Railway  Signal 
Association  and  of  the  American  Railway  Engineering  Asso- 
ciation on  the  subject  of  signaling  have  been  su  omitted  to  this 
Committee,  with  the  request  that  the  essentials  of  signaling  be 
outlined  or  defined  for  the  future  guidance  of  their  Committees. 

The  subject  has  been  carefully  analyzed  and  considered. 
There  are  three  signals  that  are  essential  in  operation  and 
therefore  fundamental,  viz : 

1.  Stop. 

2.  Proceed  with  caution. 

3.  Proceed. 

The  fundamental,  "proceed  with  caution,"  may  be  used 
with  the  same  aspect  to  govern  any  cautionary  movement; 
for  example,  when : 

(a)  Next  signal  is  "stop." 

(6)  Next  signal  is  "proceed  at  low  speed." 

(c)  Next  signal  is  "proceed  at  medium  speed." 

(d)  A  train  is  in  the  block. 

(e)  There  may  be  an  obstruction  ahead. 

There  are  two  additional  indications  which  may  be  used 
where  movements  are  to  be  made  at  a  restricted  speed,  viz : 

4.  Proceed  at  low  speed. 

5.  Proceed  at  medium  speed. 

Where  automatic  block  system  rules  are  in  effect,  a  special 
mark  of  some  distinctive  character  should  be  applied  at  the 
stop  signal. 


344  GENERAL  RAILWAY  SIGNAL  COMPANY 

The  Committee  therefore  recommends : 

SIGNAL  FUNDAMENTALS 

1.  Stop. 

2.  Proceed  with  caution. 

3.  Proceed. 

Supplementary  Indications  to  be  Used  Where  Required. 

4.  Proceed  at  low  speed. 

5.  Proceed  at  medium  speed. 

Stop  signals  operated  under  automatic  block  system  rules 
should  be  designated  by  some  distinctive  mark  to  be  deter- 
mined by  each  road  in  accordance  with  local  requirements." 

RECOMMENDATIONS  OP  COMMITTEE  I 

Your  Committee  submits  for  approval  the  following  two 
schemes  of  signaling  in  conformity  with  the  recommendations 
of  the  Committee  on  Transportation. 


SCHEME  No.  1 
Fundamentals 


1.     Stop, 


r 


2.     Proceed  with  caution, 


3.    Proceed, 


As  means  of  designating  stop  signals  operated  under  auto- 
matic block  system  rules,  the  following  are  suggested : 

1.  The  use  of  a  number  plate;  or 

2.  The  use  of  a  red  marker  light  below  and  to  the  left  of 
the  active  light ;  or 

t  3.     The  use  of  a  pointed  blade,  the  blades  of  other  signals 
giving  the  stop  indication  having  square  ends ;  or 
4.     A  combination  of  these  distinguishing  features. 


ELECTRIC  INTERLOCKING  HANDBOOK  345 


SCHEME  No.  2 

Supplementary 
Fundamentals        Indications 


1.     Stop, 


2.     Proceed  with  caution, 


3.     Proceed, 


4.     Proceed  at  low  speed, 


5.    Proceed  at  medium  speed, 


As  means  of  designating  stop  signals  operated  under  auto- 
matic block  systems  rules,  the  following  are  suggested: 

1.  The  use  of  a  number  plate;  or 

2.  The  use  of  a  red  marker  light  below  and  to  the  left  of 
the  active  light ;  or 

3.  The  use  of  a  pointed  blade,  the  blades  of  other  signals 
giving  the  stop  indication  having  square  ends ;  or 

4.  A  combination  of  these  distinguishing  features. 
Having  in  view  the  practice  of  indicating  diverging  routes 

by  several  arms  on  the  same  mast,  the  Committee  submits 
for  approval  the  following  to  establish  uniformity  in  this 
practice : 


346  GENERAL  RAILWAY  SIGNAL  COMPANY 


SCHEME  No.  3 


1.     Stop, 


or  H   or 


or 


2.     Proceed  with  caution, 


or 


3.     Proceed, 


n 


or 


or 


or 


4.     Proceed    with    caution  on   low- 
speed  route, 


5.     Proceed  on  low-speed  route,    .    .    D  or  -Q 


6.     Proceed  with  caution  on  medium- 
speed  route, 


7.     Proceed  on  medium  speed  route, 


ELECTRIC   INTERLOCKING   HANDBOOK  347 


8.     Reduce  to  medium  speed, 


As  means  of  designating  stop  signals  operated  under  auto- 
matic block  system  rules,  the  following  are  suggested: 

1.  The  use  of  a  number  plate;  or 

2.  The  use  of  a  red  marker  light  below  and  to  the  left  of  the 
active  light ;  or 

3.  The  use  of  a  pointed  blade,  the  blades  of  other  signals 
giving  the  stop  indication  having  square  ends ;   or 

4.  A  combination  of  these  distinguishing  features. 

The  above  three  schemes  are  submitted,  after  an  earnest 
effort  to  carry  out  the  Committee's  instructions  to  submit  a 
uniform  scheme  of  signaling,  with  the  idea  that  each  scheme 
is  complete  in  itself. 


SIGNAL   DEFINITIONS 

A  "non-automatic"  signal  is  one  which  is  in  no  way  con- 
trolled by  track  circuit. 

An  "automatic"  signal  is  one,  the  primary  control  of  which 
is  the  track  circuit,  or  in  other  words,  it  is  a  signal  which 
automatically  gives  indication  in  regard  to  the  integrity  of 
the  track  through  its  block. 

A  "semi-automatic"  signal  is  a  manually  controlled  auto- 
matic signal  and  may,  or  may  not,  be  interlocked.  As  to 
whether  it  is,  or  is  not,  interlocked,  will  be  apparent  from  its 
position  on  the  plan  and  its  relation  to  other  signals.  It  is 
to  be  understood  that  this  manual  control  is  direct,  and  that 
a  signal  is  not  to  be  considered  semi-automatic  because  some 
feature  of  its  control  is  dependent  upon  another  signal  which 
is  manually  controlled.  Tne  term  "slotted"  refers  only  to  a 
mechanical  signal  equipped  with  an  electric  slot, 

A  "stick  semi-automatic"  signal  is  a  semi-automatic  signal 
which  will  not  clear  automatically  after  it  has  been  put  to 
stop  by  interruption  of  the  track  circuit.  It  cannot  be  cleared 
again  until  the  manually  operated  device  controlling  it  has 
been  restored  normal  and  reversed  once  more. 

A  "non-stick-automatic"  signal  operates  automatically  as 
long  as  all  contacts  (lever,  signal,  controller,  etc.),  other  than 
track  relay  contacts  affecting  its  control,  are  closed. 


348 


GENERAL  RAILWAY   SIGNAL  COMPANY 


R.  S.  A.  SYMBOLS   FOR    SIGNALS 
^  PLATE  1   (October,  1912). 

OPERATING. 

NON  -AUTOMATIC. 

SLOTTED. 

(MECM.) 

SEMI-A  TOMATIO. 

(POW    R.) 

SPECIAL 

RIFEMNCI 

TONOTO. 

MECHAMGM 

POWER 

STICK. 

NON-STICK 

(POWER) 

r 

i     i 

i     z 

-a 

p 

fc] 

L:o:2 

Two 

POSITION 

SEMUM 

2-PosmoM. 
OT0600TOTO 
OTo7S'Oro90 

i-—-, 
j.  —  j 

i     A 

M 

A2 

A3 

^4 

a 

AS 

ID 

A6 

1     A7 

THREE 
POSITION 

2-PosrriON. 
OT090 

i     B 

33 

Bl 

11 
B2 

B3 

CD 

B4 

ED 

B5 

XI 

B6 

ta 

B7 

2-PlSITKM. 

OT045 

!       C 

Cl 

C2 

C3 

is 

04 

C5 

S3 

C6 

Isa 

C7 

2-PosmoN. 
45  TO  SO 

$ 

w 

1     01 

1^)2 

1     03 

\€ 

h€ 

Q5i 

1      07 

3-  POSITION. 
0  TO  45  TO  90 

i      E 

1" 

1     El 

fa 

1     E2 

ft 

ha 

1     E4 

1     E5 

S 

In 

& 

JE25 

NOTE:  ARMS  SHOULD  'ALWAYS  BE  SHOWN  IN  NORMAL  POSITION. 

SPECIAL-  3  POSITION    NON-AUTOMATIC,  0  TO  45  . 
SEMI  -AUTOMATIC  STICK,  45  TO  90. 

SPECIAL-  3  POSITION  NON  -AUTOMATIC,  Oio45. 
SEMI-AUTOMATIC   NON-STICK.  45  TO  90. 

S       1    ABSOLUTE   STOP  SIGNAL.            j     <'  DISTANT  SIGNAL. 

i                                                                          ! 

[">    PERMISSIVE    STOP  SIGNAL.                 C   TRAIN  ORDER  SIG.NAL. 

ENDS    OF  BLADES  IN  SYMBOLS  ARE  TO  BE  OF  THE  ACTUAL  FORMS  USED  BY  THE 
ROAO   CONCERNED.  IF  NOT  SPECIFIED  THE  ABOVE  FORMS  WILL  BE  USED  ON  PLANS. 

fTTTTj  FIXED  ARM. 

t-"-l  UPPER  9UAORWfr  SIGNAL. 
,£"_""]  LOWER  QUADRANT  SIGNAL. 

;~~]  VERTICAL  "l 

To"""                \  MARKER  LIGHTS 
t  , 
<  STAGGERED  j 

or"        ' 

•il 

4      4-     ' 

-2  

Ititi 

"iti* 

J 

T 

^1 

<L> 

v\  \ 

^_ 

KJ 

DIAGRAMS  OF  PROPORTIONS  FOR  MAK- 
ING SYMBOLS  FOR  SIGNAL  BLADES  . 

ELECTRIC   INTERLOCKING   HANDBOOK 


349 


R.  S.  A.  SYMBOLS   FOR   SIGNALS 
PLATE  2  (October,  1912). 


GROUND 
MAST. 


GROUND  MAST  WITH 
BRACKET  ATTACHMENT. 


OFFSET 
BRACKET    POST. 


T 

BRACKET 
POST. 


I:, 


SUSPENDED 
MAST. 


£^X    RING  ENCLOSED 

;  CHARACTERISTICS 

MEAN    LIGHT  SI6NA1 
ONLY. 


SMASH 


POT   SIGNAL. 


Disc  SIGNALS. 

() 


HOME  HOME  DISTANT         DISTANT         DOUBLE 

PROCEED.          STOP.  PROCEED.        CAUTION.      FUNCTIONED. 


PRESENT  SIGNAL  TO  BE  REMOVED  . 


PRESENT  SIGNAL  TO  REMAIN. 


RELATION  OF  THE  SIGNAL  TO  THE  TRACK  AND  THE  DIRECTION  OF  TRAFFIC 


RIGHT  HAND  LOCATIONS. 


RIGHT  HAND  SIGNAL  LEFT  HAND  SIGNAL. 

LEFT  HAND   LOCATIONS. 


RIGHT  HAND  SIGNAL 


LEFT  HAND  SIGNAL. 


350  GENERAL  RAILWAY  SIGNAL  COMPANY 


R.  S.  A.  LOCATION    SYMBOLS 
PLATE  3  (October,  1912). 

INSULATING  RAIL  JOINTS. 

TRACK   CIRCUITS  IN               TRACK  CIRCUIT  ON              TRACK  CIRCUIT  ON 
BOTH    DIRECTIONS.               LEFT  .  NONE  ON  RIGHT.            RIGHT,  NONE  ON  Lerr. 

IMPEDANCE  BOND.        TRAFFIC  DIRECTION.              TRACK  PAN. 

1      1                                 >-                 V-^V-A^yV^^^V^/ 

STATION.            CROSSING  GATE.            SIGNAL          SIGNAL  SUB-STATION. 

(UNUSS  8n«cr»nje  jptoneo.)                                                  POWER  STATION.                                       -- 

•                                      - 

)       \     >  k      )  —  *  —  (       )=*  k 

TUNNEL.     BRIDGE  OR  VIADUCT.    DRAWBRIDGE.           LIFT  BRIDGE. 

NOTE:   STATJ  WMITMIK   DH*.HM.r-TMW06«  o«  T«*OOSM  Bm«M. 

T         T          T         II           ji 

•  ; 

1                   I                     ii 

OVERHEAD             SIGNAL              HIGHWAY             RAILWAY           PROPOSED  RAILWAY 
BRIDGE.             B«IOGE.             CROSSING.            CROSSING.               CROSSING. 
MOTE:  SPtcirr  wMtTMM  Sn*u  w  EUCTHIC  Rv  Cuossiw. 

MAIL  CRANE.      WATER  TANK.  WATER  COLUMN.  TRACK  INSTRUMENT.     TORPEDO  MACHINE. 

TRAIN  STOPS. 

A        A        A        A        A 

™              \w              w              U 

^          STOP. 

• 

<-~iJr                *^W 

e, 
CLEAR. 

NON-  AUTOMATIC.               SLOTTED.         SEMI- 
MECHANICAL.         POWER.                            AUTOMATIC. 

AUTOMATIC. 

1  ^^^^              «f  —  ^^                                          1  _^^ 

DO      * 
POWER  SWITCH              INSULATED                TURN-OUT 
MACHINE.                SWITCH  ROD.          AND  SWITCH  STAND. 

^L 

ELECTRIC 
SWITCH  LOCK. 

ELECTRIC  INTERLOCKING  HANDBOOK 


351 


11.  S.  A.  LOCATION    SYMBOLS 
PLATE  4  (October,  1912). 


RELAY  Box.         JUNCTION  Box.        TERMINAL  Box.  LIGHTNING  ARRESTER 

Box. 


$ CAPACITY 

BATTERY  CHUTE  . 


RELAY   MX  CAPACITY PT\ 

CHUTE   CAPACITY kXd 


1 


RELAY  Box  AND  POST.  BATTERY  CHUTE, RELAY 

Box  AND  POST  COMBINED  . 


NOTE  :  TYPE  Of  INDICATOR 

TO  K  COVERED  BY  — 

(_)                  6ENERALNDTE.  () 

I  I 


SWITCH   Box  LOCATION  .       SWITCH  INDICATOR  . 


SWITCH  INDICATOR 
AND  SWITCH  Box. 


A 

OD 


CABLE  POST    WITH  ONE      WITH  Two     WITH  RELAY     WITH  RELAY     WITH  RELAY 
ONLY.        INDICATOR.     INDICATORS.        Box.         Box  AND  ONE     Box  AND  Two 

INDICATOR  .      INDICATORS  . 


5  J    ABOVE  SURFACE . 


5}-  HALF  ABOVE  SURFACE. 


M5J    BCLOW  SURFACE. 

(FI6URES    INDICATE   CAPACITY) 


HIGHWAY  CROSSING  BELL. 


>  BATTERY  SHELTER. 


OR 


TRACK  BATTERY 


352 


GENERAL  RAILWAY   SIGNAL  COMPANY 


R.  S.  A.  LOCATION    SYMBOLS 
PLATE  5  (October,  1912). 


INTERLOCKED  SWITCHES  AND  DERAILS. 


SWITCH -SET  FOR  TURN-OUT. 


DERAIL-  POINT  TYPE-DERAILING. 


SWITCH -SET  FOR  STRAIGHT  TRACK. 


DERAIL-  POINT  TYPE-NON-DERAIUNG  . 


DERAIL -LIFTING  RAILTYPE-DERAILING.  DERAIL- LIFTING  RAILTYPE-NON-DCRAILING. 


DERAIL -LIFTING  BLOCK  TYPE -DERAILING.          DERAIL- LIFTING  BLOCK  TYPE-NON-DERAIUNG. 

NOTE:  NON-INTERLOCKED   SWITCHES  AND  OEKAItS  TO  BE  SHOWN 
SAME  AS  ABOVE  EXCEPT  SHAOIN6  IN  TRIANGLES  OMITTED. 

RUNS 

OF  CONNECTIONS. 

PIPE-WIRE  (MECH.). 
WIRE  DUCT. 


COMPRESSED  AIR. 
PIPE-WIRE  AND  DUCT. 
PIPE  -WIRE  AND  AIR. 
DUCT  AND  AIR. 

PIPE  -WlRETDUCT  AND  AIR. 


BOLT  LOCKED  SWITCH.  3"WAY- 

5.LM.-Swircn*LocK  MOVEMENT.       CRANKS. 
F.P.L.-FAGING  POINT  LOCK.  J-WAY. 


COMPENSATOR. 


ARROW  INDICATES  DIRECTION 
OF  MOVEMENT  OF  PIPE  LINE- 
NORMAL  TO  REVERSE. 


OIL  ENCLOSED  PIPE  LINE. 


3-WA.Y. 


MAN-HOLE. 


r^Ti  INTERLOCKING  OR  BLOCK  STATION.   ISZTI 

I/F\I  SH9WM6  RELATIVE  POSITION  OF  STATION.  OPERATOR  AND  TRACK.  V—1  M 
OPERATOR  FACING  TRACK  .  OPERATOR  WITH  BACK  TO  TRACK. 

NOTE:  UNLESS  OTHERWISE  SPECIFIED  ON  PLAN  IT  WILL  BE  ASSUMED  THAT  WHERE  AM 

INTERLOCKED  SIGNAL  IS  SHOWN  CLEAR  OR  A  DERAIL  SHOWN  IN  NON-DERAILING 

POSITION  THE  CONTROLLING  LEVER  IS  REVERSED,  AND  THAT  ALL  OTHER  LEVERS  ARE  NORMAL. 


ELECTRIC   INTERLOCKING   HANDBOOK 


353 


R.  S.  A.  LOCATION   SYMBOLS 
PLATE  6  (October,  1912). 


INTERLOCKED  SWITCHES, DERAILS, ETC. 

6 


SINGLE  LINE  PLAN  . 
EXPLANATION 


1  -  SIMPLE  TURN-OUT. 

2  -  SIMPU  CROSS- WER  . 

3  -  Owftit-  POINT  Tm  . 
4 -SIMILE  SLIP  SWITCH. 


5 -DOUBLE  SLIP  SWITCH. 
6-MovABu  POINT  Cnossme  Fooe.  (M.P.F.) 
7 -SINGLE  SLIP  SWITCH  WTM  M.P.F. 
8 -DOUBLE  SLIP  SWITCH  WITH  M.P.F. 


ROCKING  SHAFT  LEAD-OUT. 


1234      6789 

CRANK  LEAD-OUT. 


DEFLECTING  BAR  LEAD-OUT. 


7      V 

123  £78 

VERTICAL    DEFLECTING    BARS. 


354  GENERAL  RAILWAY  SIGNAL  COMPANY 

R.  S.  A.  SYMBOLS   FOR   RELAYS,  INDICATORS    AND    LOCKS 
PLATE  7  (October,  1912). 


RELAYS,  INDICATORS  AND  LOCKS. 

ELEMENTS  OF  SYMBOLS    T~T 

TO  BE  COMBINED  AS         O  D  .  C  .  ELECTRO  MAGNET. 

NECESSARY.  .LL 

1X1        A. C. ELECTRO  MAGNET. 
]„;       ]._[        COIL  ENERGIZED  OR  DE-ENERGIZED  . 
i..i.j       i._i|       NEUTRAL  FRONT  CONTACT  -  CLOSED  o«  OPEN  . 

l.J.        NEUTRAL  BACK  CONTACT  -  CLOSED  OR  OPEN  . 
POLARIZED  ARMATURE  -  WITH  CONTACTS. 


3  -  POSITION  ARMATURE  -  WITH  CONTACTS  . 


HIGH  CURRENT  CONTACT. 
l..l|       MAGNETIC  BLOW-OUT  CONTACT. 

iQ.         BELL  ATTACHMENT. 

t*"f 

im         DOUBLE  WINDING -SPECIFY  IF  DIFFERENTIAL. 

f-T 

jfsi         SLOW  ACTING. 

&    Tf, 

i..i        L.I        Disc TVPE  INDICATOR.  O= Disc  INVISIBLE.  •  "Disc  VISIBLE. 
1°       1^      f= 
i..i    i.i    i-.l   i..i        SEMAPHORE  TYPE  INDICATOR,  f83- 3- POSITION. 

-o- 

M  OR  Mi  OR  Ml      WIRE  WOUND  ROTOR 

—         -*> 

3l-^i°R   i-i  ,      STATIONARY  WINDINS  .  IrSi.-  HIGH  VOLTAGE  WINDING  . 

ELECTRIC  LOCK-  SHOW  SEGMENTS  FOR  LEVER  IN  NORMAL 
POSITION  . 
(SEE  NEXT  PAGE  FOR- EXAMPLES  OF  COMBINATIONS.) 


ELECTRIC   INTERLOCKING   HANDBOOK  355 

R.  S.  A.  SYMBOLS   FOR   RELAYS,   INDICATORS  AND  LOCKS 
PLATE  8  (October,  1912). 


RELAYS  ,  INDICATORS  AND  LOCKS. 

EXAMPLES   OF  COMBINATIONS. 

FT  D.C.  RELAY-  NEUTRAL- ENERGIZED  -  • 

1,1  ONE  INDEPENDENT  FRONT  CONTACT  CLOSED  - 

•  ONE  INDEPENDENT  BACK  CONTACT  OPEN. 

&  D.C.  RELAY -POLARIZED -ENERGIZED  - 

Two  COMBINATION  FRONT  AND  BACK  NEUTRAL  CONTACTS  - 
0  *  t  Two  POLARIZED  CONTACTS  CLOSED  — 

Two  POLARIZED  CONTACTS  OPEN. 


J.L 


fi. 


•o 


-o 

A 


O.C.  INDICATOR-  SEMAPHORE  Type -ENERGIZED  - 
THREE  FRONT  CONTACTS  ..  CLOSED  — 
BELL  ATTACHMENT  . 


O.C.  INDICATOR -SEMAPHORE  TYPE -ARM  HORIZONTAL- 
ENERGIZED  -  WITHOUT  CONTACTS . 
NOTE  :  INDICATORS  (OR  REPEATERS)  WITHOUT  CONTACTS  SHOULD  BE  SHOWN 

WITH  ARMATURES  TO  INDICATE  WHETHER  ENERGIZED  OR  DC-ENER- 
GIZED . 

A.C.RELAY-ONE  ENERGIZING  CIRCUIT  TYPE  (SINGLE  PHASE) 

ENERGIZED  — ONE  FRONT  CONTACT. 


A. C. RELAY- Two  ENERGIZING  CIRCUIT  TYPE-  ENERGIZED  • 
WIRE  WOUND  ROTOR  - 
Two  NEUTRAL  FRONT  CONTACTS  . 


A.C.  RELAY-Two  ENERGIZINS  CIRCUIT  TYPE  -  ENERBIZED  — 
WIRE  WOUND  ROTOR  - 
Two  POLARIZED  CONTACTS. 


A.C  RELAY-Two  ENERSIZING  CIRCUIT  TYPE -ENERGIZED' 
STATIONARY  WINDINGS  - 
ONE  NEUTRAL  FRONT  CONTACT  — 
.  Two  3- POSITION  CONTACTS. 

t  '    t 

D.C. INTERLOCKED  RELAY. 


O.C. ELECTRIC  BELL. 

DESI6NATE  RESISTANCE  IN  OHMS  OF  ALL  D.C. RELAYS,  INDICATORS  AND   LOCKS. 


356 


GENERAL   RAILWAY   SIGNAL  COMPANY 


R.  S.  A.  SYMBOLS   FOR   CIRCUIT   CONTROLLERS 
PLATE  9  (October,  1912). 


CIRCUIT  CONTROLLERS  OPERATED  BY  LEVERS. 

Use  EITHER  LETTER  SYSTEM  OR  GRAPHIC  SYSTEM. 


ievEBSWTH  ExntcMi  END  POSITION  AS  NORMAL  . 

N-  FULL  NORMAL  POSITION  OF  LEVER 
B- NORMAL  INDICATION  POSITION  . 

C-GCNTRAL  POSITION. 

0- REVERSE  INDICATION  POSITION. 
R-Fuu.  REVERSE  POSITION. 


LEVERS  WITH  MIDDLE  POSITION  AS  NORMAL. 
N-NORMAL  POSITION. 
L-Fuu.  REVERSE  POSITION  TO  THE  LEFT. 
B  -INDICATION  POSITION  TO  THE  LEFT. 
0 -INDICATION  POSITION  TO  THE  RIGHT. 
R-Fuu  REVERSE  POSITION  TO  THE  RIGHT. 


LETTER 
SYMBOL. 


B     N     D 


NOTE:  HEAVY  HORIZONTAL  LINES  INDICATE  PORTION  or  CYCLE  OF  LEVER  THROUGH  WHICH  CIRCUIT  is  CLOSED 


ELECTRIC  INTERLOCKING   HANDBOOK 


357 


R.  S.  A.  SYMBOLS   FOR   CIRCUIT   CONTROLLERS 
PLATE  10  (October,  1912). 

CIRCUIT  CONTROLLERS  OPERATED  BY  SIGNALS. 

UPPER  QUADRANT.  LOWER   QUADRANT. 


CLOSED  AT  0   ONLY. 


3 -POSITION 
SIGNALS. 


60-70  OB 
75°  SIGNALS. 


CLOSED  AT  45  ONLY. 


CLOSED  AT  90  ONLY. 


CLOSED  0  TO  45 


CLOSED  45  TO  90 


CLOSED  AT  0  Owtx. 

CLOSED  IN  CLEAR 
POSITION  ONLY. 


CLOSED. 
OPEN. 


:=t=: 


CIRCUIT  CONTROLLER  OPERATED  BY  LOCKING 
SWITCH    CIRCUIT    CONTROLLER.          MECHANISM  OF  A  SWITCH  MOVEMENT. 


CLOSED. 
OPEN. 


BRIDGE  CIRCUIT  CONTROLLER. 


POLE  CHANGING  CIRCUIT  CONTROLLER. 


SPRING  HAND  KEY  OR  PUSH  BUTTON. 


CIRCUIT  SWITCH. 


358 


GENERAL  RAILWAY  SIGNAL  COMPANY 


R.  S.  A.  SYMBOLS  FOR  CIRCUIT  CONTROLLERS,  RELEASES,  ETC. 
PLATE  11   (October,  1912). 


MANUAL  TIME  RELEASE  . 
(ELECTRIC) 


MANUAL  TIME  RELEASE,  . 
(ELECTRO -MECHAN'L.) 


AUTOMATIC  TIME  RELEASE  . 

(ELECTRIC) 


EMERGENCY  RELEASE  . 
(ELECTRIC) 


f 

FLOOR  PUSH, 


/I 


OPEN.  CLOSED. 

LATCH  CONTACT.      TRACK  INSTRUMENT  CONTACT. 

KNIFE  SWITCHES. 


d)  (DO  O  O  (D 

RHEOSTAT.     SINGLE  POLE.  DOUBLE  POLE.     SINGLE  POLE.  DOUBLE  POLE. 
SINGLE  THROW.  DOUBLE  THROW. 

QUICK  ACTING  CIRCUIT  CONTROLLERS  MAY  BE  DISTINGUISHED  BY  THE  LETTER  "9" 


— sAA/V — 

FIXED  RESISTANCE  .        VARIABLE  RESISTANCE  . 


IMPEDANCE    WITHOUT         IMPEDANCE  WITH 
IRON  CORE.  IRON  CORE 


FUSE  . 


CONDENSER. 


ELECTRIC   INTERLOCKING   HANDBOOK 


359 


R.  S.  A.  SYMBOLS  FOR  BATTERIES,  GENERATORS,  MOTORS,  ETC. 
PLATE  12  (October,  1912). 


BATTERY. 


A.C.TERMINALS. 


CELLS  IN  MULTIPLE.  CELLS  IN  SERIES. 

SPECIFY  TYPE  AMD  NUMBER  OF  CELLS  .  "ECTi FI ER  . 

D  »  DRY   BATTERY. 
6  »  GRAVITY  »» 
P  •  POTASH   »» 
S  »  STORAGE  »» 

EXAMPLES:  I6P,  IDS,  ETC. 


D.C.TERMINALS. 


roooooWj 


I-SECONDARY.  2-0»  MORE  SECONDARIES. 

TRANSFORMERS. 


(M) 

O.C.  MOTOR. 


A.C.  GENERATOR. 

S 

AMMETER  . 


D.C.GENERATOR. 


A.C.  MOTOR. 


M) — (G 

D.C.-D.C.  MOTOR-GENERATOR.    A.C.-D.C.  MOTOR- 


sY> 

VOLTMETER. 


WATTMETER.        TELEPHONE 


SINGLE.  DOUBLE. 

INCANDESCENT  LAMP.         LIGHTNING  ARRESTER.  TERMINALS. 


WIRES  CROSS  . 


WIRES  JOIN. 


GROUND. 


"  COMMON  "  WIRE  . 


TRACK  CIRCUIT  WIRE. 


OTHER  THAN  "  COMMON" WIRE. 


DIRECTION  OF  CURRENT. 


SECTION  XVII 


GENERAL   DATA 


COVERING  THE  WEIGHTS  OF  G.  R.  S. 
INTERLOCKING  APPARATUS,  MAINTE- 
NANCE TOOLS  REQUIRED,  BELTING, 
PULLEYS,  SWITCH-LEADS  AND  CROSS- 
OVERS, TABLES  OF  NAILS,  SCREWS, 
NUTS,  ETC.,  TABLES  OF  SPECIFIC 
GRAVITIES,  WEIGHTS  AND  MEASURES, 
FAHRENHEIT  AND  CENTIGRADE  TEM- 
PERATURES, FRACTIONS  AND  DECIMAL 
EQUIVALENTS,  POWERS  AND  ROOTS, 
AREAS  AND  CIRCUMFERENCES  OF 
CIRCLES,  ETC.,  ETC. 


GENERAL  DATA 


SHIPPING  WEIGHTS   OF   G.  R.  S.  APPARATUS 

Shipping 

CHARGING  APPARATUS  pJS?' 

D.  C.  Generator,  capacity  1.25  K.  W.  (Page  169),    .    .  290 

D.  C.  Generator,  capacity  2.50  K.  W., 340 

D.  C.  Generator,  capacity  3.25  K.  W., 500 

D.  C.-D.  C.  Motor  Generator  Set,  capacity  1.25  K.  W. 

(Page  168), 600 

D.  C.-D.  C.  Motor  Generator  Set,  capacity  2.40  K.  W.,  800 

D.  C.-D.  C.  Motor  Generator  Set,  capacity  3.25  K.  W.,  1050 

The  above  weights  cover  the  necessary  starting  devices 
and  field  rheostats. 

TRANSFORMERS 

Type  K,  air  cooled  (Fig.  249), 20 

Type   LI,   complete  with   oil,   hanger,  and   cut-outs 

(Fig.  247), 130 

Type  L2,  complete  with   oil,  hanger,  and  cut-outs,  175 

Type   L3,   complete  with  oil,  hanger,  and  cut-outs,  210 

POWER  SWITCHBOARDS 

•Board,  24"  x  36",  controlling  1  H.  V.  battery  and  1 
generator  (Fig.  117), 210 

Board,  24"  x  48",  controlling  1  H.  V.  battery,  duplicate 
sets  of  L.  V.  battery  and  1  generator  (Fig.  119),  .  .  410 

Board,  48"  x  48",  controlling  1  H.  V.  battery,  duplicate 
sets  of  L.  V.  battery,  4  sets  track  battery,  and  1  gen- 
erator (Fig.  121), 600 

OPERATING  SWITCHBOARDS 

1  Section  Board,  12"  x  36",  no  voltmeter  (Fig.  128),    .  280 

2  Section  Board,  24"  x  36",  no  voltmeter, 530 

3  Section  Board,  36"  x  36",  no  voltmeter, 800 

1  Section  Board,  12"  x  48",  with  voltmeter, 350 

Panel,  12"  x  12",  with  voltmeter, 70 

LIGHTING  PANELS  FOR  POWER  AND  OPERATING  BOARDS 

Panel,  12"  x  12",  with  5  S.  P.  S.  T.  switches  (Fig.  130), .  90 

Panel,  12"  x  18",  with  10  S.  P.  S.  T.  switches  (Fig.  132), .  110 
Panel,  12"  x  24",  with  6  D.  P.  S.  T.  or  12  S.  P.  S.  T. 

switches, 150 

Panel,  12"  x  36",  with  9  D.  P.  S.  T.  or  18  S.  P.  S.  T. 

switches, 190 

INTERLOCKING  MACHINE 
Model  2  —  1  tier  locking. 

Per  lever, 90 

Per  spare  space, 70 


364  GENERAL  RAILWAY  SIGNAL  COMPANY 

Shi 
We 

Model  2  —  2  tier  locking.  Pounds' 

Per  lever,  ...................  100 

Per  spare  space,  ................  80 

Model  2  —  3  tier  locking  (Fig.  137). 

Per  lever,  ...................  110 

Per  spare  space,  ................  90 

Model  2  —  4  tier  locking. 

Per  lever,  ...................  120 

Per  spare  space,  ................  100 

Unit  Type  —  1  tier  locking. 

Per  lever,  ......    .............  110 

Per  spare  space,   ................  80 

Unit  Type  —  2  tier  locking. 

Per  lever,  .    .    .................  120 

Per  spare  space,   ............  *'!."..  90 

Unit  Type  —  3  tier  locking  (Fig.  136). 

Per  lever,  ...................  130 

Per  spare  space,  ................  100 

Unit  Type  —  4  tier  locking. 

Per  lever,  ...................  150 

Per  spare  space,  ................  120 

The  above  weights  for  machines  complete  with  levers, 
individual  polarized  relays,  riveted  locking,  and  cabinet. 

Complete  Set  of  Locking  —  Average  weights  per  work- 
ing lever. 

1  Tier  of  Locking,    ................  10 

2  Tiers  of  Locking,  ................  15 

3  Tiers  of  Locking,  ................  20 

4  Tiers  of  Locking,  ................  25 

Separate  Lever  complete  with  polarized  relay,  ....  40 

Lever  Lock  (Fig.  141)  applied  to  machine,     .....  10 

SWITCH  LAYOUTS    (Crank  Connected) 

Single  Switch,  Model  2  switch  machine  (Fig.  163),  .  .  1000 
Single  Switch,  Model  4  switch  machine  (Fig.  162),  .  .  1500 
Split  Point  Derail,  Model  2  switch  machine  (Fig.  165),  .  1000 


Split  Point  Derail,  Model  4  switch  machine  (Fig.  164),  .   1500 

(Fig.  167 
Hayes  Derail,  Model  4  switch  machine  (Fig.  166),    .    .   1600 


,  . 

Hayes  Derail,  Model  2  switch  machine  (Fig.  167),    .    .   1100 


Wharton  or  Morden  Derail,  Model  2  switch  machine 

(Fig.  169),     ..................   1100 

Wharton  or  Morden  Derail,  Model  4  switch  machine 

(Fig.  168),     ..................   1600 

Single  Slip  Switch  (one  end),  Model  2  switch  machine 

(Fig.  171),     ..................   1000 

Single  Slip  Switch  (one  end),  Model  4  switch  machine 

(Fig.  170),     ..................   1500 

Double  Slip  Switch  (one  end),  Model  2  switch  machine 

(Fig.  173),     ..................   1200 


ELECTRIC  INTERLOCKING  HANDBOOK  365 


Pounds 

Double  Slip  Switch  (one  end),  Model  4  switch  machine 
(Fig.  172), 1800 

Movable  Point  Frog,  Model  2  switch  machine  (Figs. 
175,  177), 1600 

Movable  Point  Frog,  Model  4  switch  machine  (Figs. 
174,  176), 2000 

The  above  weights  are  for  switch  machines  complete 
with  tie  plates,  throw  rod,  lock  rod,  No.  1  switch  rod,  rail 
braces,  and  all  necessary  bolts,  nuts,  and  cotters.  Switch 
connections  insulated.  Weights  for  Model  4  switch 
machine  layouts  include  switch  circuit  controller  and 
connections.  Weights  do  not  include  detector  bars. 

Model  2  Switch  Machine  (Fig.  159), 500 

Model  4  Switch  Machine  for  single  switch  or  derail 

(Fig.  161), 850 

Model  4  Switch  Machine  for  movable  point  frog  or 

double  slip  switch  (Fig.  160), 950 

DETECTOR  BAR  LAYOUTS    (Crank  Connected) 

1  Bar,  same  side  for  Model  2  or  Model  4  switch  machine,    360 

1  Bar,  opposite  side  for  Model  2  or  Model  4  switch 
machine, 460 

2  Bars,  for  Model  2  or  Model  4  switch  machine,    .    .    .     770 
1  Bar,  for  two  Model  2  or  Model  4  switch  machines,    .     780 

The  above  weights  for  detector  bar  layouts  are  com- 
plete with  all  connections  and  necessary  bolts,  nuts,  etc. 
Connections  insulated. 

SIGNALS  —  RSA  DIMENSIONS 

Pipe  Bracket  Post  complete,  narrow  deck, 3400 

Pipe  Bracket  Post  complete,  wide  deck, 3800 

1  Arm  Ground  Signal  complete,  22'  6"  base  to  center 
of  arm, 1270 

1  Arm  Ground  Signal  complete,  29'  6"  base  to  center 

of  arm, 1430 

2  Arm  Ground  Signal  complete,  22'  6"  base  to  center 

of  lower  arm, 1850 

2  Arm  Ground  Signal  complete,  28'  6"  base  to  center 

of  lower  arm, 2000 

3  Arm  Ground  Signal  complete,  22'  6"  base  to  center 

of  lower  arm, 2420 

1  Arm  Bracket  or  Bridge  Signal  complete,  3'  6"  base 
to  center  of  arm, 710 

1  Arm  Bracket  or  Bridge  Signal  complete,  10'  6"  base 

to  center  of  arm, 900 

2  Arm  Bracket  or  Bridge  Signal  complete,  3'  6"  base 

to  center  of  lower  arm, 1310 


366  GENERAL  RAILWAY  SIGNAL  COMPANY 


Shipping 
Weights. 
Pounds 

2  Arm  Bracket  or  Bridge  Signal  complete,  9'  6"  base 

to  center  of  lower  arm, 1450 

3  Arm  Bracket  or  Bridge  Signal  complete,  3'  6"  base 

to  center  of  lower  arm, 1860 

The  above  signals  complete  with  mechanism,  ladders, 
spectacles,  blades,  lamp  brackets,  foundation  bolts,  etc. 

Cantilever  Bracket  complete, 200 

Dummy  Mast, 300 

Fixed  Arm  complete, 130 

Model  2 A,  110  Volt  Signal  Mechanism  complete,  with 

clamp  bearing  (Fig.  199), 350 

DWARF  SIGNALS 

Model  2A  Dwarf  Signal  complete  (Figs.  204,  205),    .    .  380 

Model  2,  1  Arm  Dwarf  Signal  complete  (Fig.  207),  .    .  150 

Model  2,  2  Arm  Dwarf  Signal  complete  (Fig.  206),   .    .  300 

Model  3,  1  Arm  Dwarf  Signal  complete  (Fig.  208),   .   .  140 

The  above   signals   complete   with   spectacle,   blade, 
lamp  bracket,  foundation  bolts,  etc. 

SWITCH  CIRCUIT  CONTROLLERS 

Model  5,  Form  A  Switch  Circuit  Controller  (Fig.  186),  60 

Model  3,  Switch  Circuit  Controller,  4  circuits  (Fig.  185),  40 

Model  3,  Switch  Circuit  Controller,  8  circuits, 60 

Add  for  Short  Operating  Rod, 15 

Add  for  Long  Operating  Rod, 25 

RELAYS  AND  INDICATORS 

Model  9,  D.  C.  Relay,  4-way  (Figs.  228,  229),  ....  30 

Model  9,  D.  C.  Relay,  8-way, 35 

Model  1,  D.  C.  Relay,  not  inclosed, 30 

Model  1,  D.  C.  Relay,  inclosed, 35 

Model  9,  Tower  Indicator,  4-way  (Fig.  230), 30 

Model  9,  Tower  Indicator,  8-way 40 

Model  9,  Indicator  Group,  with  4-way  indicators 

(Fig.  83),  per  indicator, 35 

Model  9,  Indicator,  Group  with  8-way  indicators, 

per  indicator, 45 

Model  2,  Form  A  Polyphase  Relay,  4-way  (Fig.  235),  65 

Model  2,  Form  A  Polyphase  Relay,  6-way, 70 

Model  2,  Model  3,  or  Model  Z,  Form  B  Relay,  4-way 

(Fig.  232), 40 

Model  2,  Model  3,  or  Model  Z,  Form  B  Relay,  6-way,  45 
Model  2,  Model  3,  or  Model  Z,  Form  B  Indicating 

Relay,  4-way  (Fig.  234), 50 

Model  2,  Model  3,  or  Model  Z,  Form  B  Indicating  < 

Relay,  6-way, ,    .    ,  55 


ELECTRIC   INTERLOCKING   HANDBOOK  367 


Shipping 
Weights. 
Pounds 

Model  2,  Model  3,  or  Model  Z,  Form  B  Tower  Indi- 
cator (Fig.  233), 35 

RELAY  BOXES 

1-way  Iron  Box  for  D.  C.  relays, 120 

2-way  Iron  Box  for  D.  C.  relays  (Fig.  242) 160 

3-way  Iron  Box  for  D.  C.  relays, 250 

4-way  Iron  Box  for  D.  C.  relays, 225 

1-way  Wood  Box  for  D.  C.  relays, 25 

2-way  Wood  Box  for  D.  C.  relays  (Fig.  243),     ....  35 

3-way  Wood  Box  for  D.  C.  relays 50 

1-way  Wood  Box  for  Model  2  Form  A  relays, 40 

2-way  Wood  Box  for  Model  2  Form  A  relays  (Fig.  241),  55 

3-way  Wood  Box  for  Model  2  Form  A  relays, 75 

The  above  boxes  complete  with  terminal  board  and 
U  bolts  or  bracket  for  mounting  on  stub  pole. 

Add  for  mounting  on  signal  mast, 20 

Posts  for  mounting  relay  box  on  foundation,     ....  40 

Post  for  mounting  relay  box  on  battery  chute,  ....  70 

BATTERY  CHUTES  (Page  292) 

6-ft.  Single  Battery  Chute,  complete  with  elevator,  .    .  260 


7-ft.  Single  Battery  Chute,  complete  with  elevator, 
8-ft.  Single  Battery  Chute,  complete  with  elevator,  . 
9-ft.  Single  Battery  Chute,  complete  with  elevator,  . 
7-ft.  Double  Battery  Chute,  complete  with  elevator, 
9-ft.  Double  Battery  Chute,  complete  with  elevator, 


290 
350 
390 
520 
650 


IMPEDANCE  BONDS 

Size  1,  Form  C  Bond  (Fig.  91),  per  single  bond,  ...  610 
Size  2,  Form  B  Bond  (Fig.  92),  per  single  bond,  ...  420 
Size  3,  Form  A  Bond  (Fig.  92),  per  single  bond,  .  .  .  250 

TRUNKING,  STAKES,  AND  JUNCTION  BOXES  (Figs.  270,  271) 

3"  x  4"  Trunking  with  Capping,  pine,  per  1,000  lineal 
feet, 5300 

3"  x  4"  Trunking  with  Capping,  cedar,  per  1,000  lineal 
feet, 3000 

Built-Up  Trunking,  pine,  per  1,000  feet,  B.  M 3350 


Built-Up  Trunking,  cedar,  per  1,000  feet,  B.  M.,  . 
Oak  Stakes,  3"  x  V  x  3'  0"  (square  end),  .... 
Oak  Stakes,  3"  x  4"  x  4'  0"  (square  end);  .... 
Cedar  Stakes,  4"  diameter  x  3'  0"  (pointed),  .  .  . 

Cedar  Stakes,  4"  diameter  x  3'  6"  (pointed), 10 

Junction  Box,  inside  dimensions,  15W  x  15W  x  11",   .       40 
Junction  Box,  inside  dimensions,  16"  x  16"  x  20",     .    .       60 


1900 
10 
15 
10 


368 


GENERAL  RAILWAY  SIGNAL  COMPANY 


ELECTRIC   INTERIX)CKING   HANDBOOK  369 

COMPLETE   LIST  OF  MAINTENANCE   TOOLS 
REQUIRED  AT  ELECTRIC   INTER- 
LOCKING  PLANTS 

BLACKSMITH  TOOLS 
1  Anvil. 
1  Forge. 

1  Set  of  tools,  including  10  pound  hammer,  cold  cutter  and 
%"  punch. 

CARPENTERS  TOOLS 
1  18"  square. 
1  Jack  plane. 
1  Brace  with  set  of  bits. 
1  1%e"  single  lip  car  bit  14"  long. 
1  %*  wood  chisel. 
1  26"  No.  9  hand  saw. 
1  Hand  axe. 
1  Adze. 
1  Claw  hammer. 

ELECTRICAL  TOOLS 

1  Soldering  furnace-pot  and  two  ladles. 

1  Small  soldering  copper. 

2  Screw  drivers,  6"  and  10". 
1  Aligator  pliers,  8". 

1  Side-cutting  pliers,  7". 
1  Contact  adjuster. 

1  Binding-post  wrench. 

2  Socket  wrenches  for  1A"  hexagon  nut. 
1  Wrench  for  signal  circuit  breaker. 

1  Crank  for  switch  motor. 

1  Hydromotor. 

1  Portable  volt-ammeter. 

1  Solid  wrench  for  %"  hexagon  nuts. 

LINE  CIRCUIT  TOOLS 

1  Belt  with  safety. 
1  Pair  16"  climbers. 

1  "Come  along"  with  blocks. 

2  Connectors. 

PIPE  TOOLS 
(For  pipe  connected  detector  bars.) 

1  Stilson  wrench. 

2  Pipe  rivet  punches. 
1  Pipe  cutter. 

1  Stock  with  1"  right-hand  dies. 

SWITCH  FITTING  TOOLS 

1  Machinist  hammer. 
1  Center  punch. 


370  GENERAL  RAILWAY  SIGNAL  COMPANY 

2  Cold  chisels. 

1  12"  tommy  bar — bent  on  both  ends. 

1  20"  tommy  bar — bent  on  chisel  end  only. 

1  Packer  ratchet  with  His"  and  13/i6"  drill. 

1  "Old  man"  for  drilling  rail. 

2  Switch-adjusting  wrenches. 

3  Two-man  "T "  socket  wrenches  for  %"  square  and  hexagon 

nut,  and  %"  lag  screws. 
2  "T"  socket  wrenches  for  %"  and  W  lag  screws. 

4  Solid  "S"  wrenches  for  %"  and  %"  bolts  with  square  or 

hexagon  nut. 
1  Solid  wrench  for  detector  bar  clips. 

1  14"  Monkey  wrench. 

2  Reamers,  %"  and  %". 
1  14"  Stilson  wrench. 

1  6"  Westcott  wrench. 

4  Files:    one-14"  flat  bastard,  one-10"  flat  smooth,  one-12" 

half-round  bastard,  one-12"  round. 
4  Files:    two-6"  rat  tail,  two  saw  files. 

TRACK  TOOLS 
1  Spike  maul. 
1  Spike  puller. 
1  Claw  bar. 
1  Track  wrench. 
1  Track  shovel. 
1  Barn  broom. 
1  Railroad  pick. 

TRACK-CIRCUIT  TOOLS 

1  Bonding  drill  with  twelve  %2"  twist  drills. 

2  Channel  pins  punches. 

1  Channel  pin  set  (slotted). 

MISCELLANEOUS 

1  Workbench  with  combination  vise. 

1  Drill  press  with  drills. 

1  Set  taps  and  dies  with  stock  W  to  1". 

1  Breast  drill  with  set  of  drills  W  to  %"  by  32nds. 

1  Bench  emery  wheel. 

1  Hack  saw,  12  blades. 

1  Large  spout  oiler  (1  quart). 

1  9"  spout  oiler  (1  pint). 

1  6"  spout  oiler  04  pint). 

2  Water  pails. 

1  Canvas  tool  bag. 


ELECTRIC   INTERLOCKING   HANDBOOK 


371 


MODEL   1   FORM  A   LIGHTNING   ARRESTER 

Fig.  276  illustrates  the  G.  R.  S.  Co.'s  Model  1  Form  A  light- 
ning arrester,  designed  for  use  on  signal,  telegraph,  telephone, 
crossing  alarm  circuits,  etc. 

The  arrester  has  a  high  efficiency,  i.  e.,  a  high  reactance 
and  negligible  ohmic  resistance.  This  high  reactance  is 
maintained  under  all  conditions  of  frequency  and  current 
owing  to  the  fact  that  no  iron  is  used  in  the  core  of  the  react- 
ance coil. 

The  arrester  is  small  (1%6*x4%*x4%«?)  and  may  be  assem- 
bled in  banks  on  one  inch 
centers.  Connectors  between 
the  ground  plates  are  provided, 
which  form  a  buss  bar  of  ample 
carrying  capacity,  thereby  mak- 
ing requisite  but  one  ground 
connection  for  any  number  of 
arresters.  Multiple  point  dis- 
charge plates  are  provided 
instead  of  the  single  point  type 
or  one  having  a  circular  sur- 
face. The  parts  used  in  the 
arrester  construction  are  few, 
none  of  them  being  delicate 
or  easily  broken.  The  con- 
nections are  all  in  front,  thus 
allowing  it  to  be  easily  installed 
pr^  x  /  ^TH  and  inspected. 

I!  i.  .  L_!  ill        The  Model   1   Form  A  uses 

the  same  component  parts  as 
the  Model  1  arrester,  thou- 
sands of  which  are  at  the 
present  time  in  service,  many 
them  showing  evidence  of 
having  taken  care  of  heavy 
discharges  without  injury  re- 
sulting to  the  arrester  or  the 
protected  apparatus. 

The  arresters  should  be  grounded  through  two  No.  8 
B.  &  S.  gauge  copper  wires,  insulated  above  the  ground. 
The  wires  should  be  wrapped  around  and  soldered  to  a  gal- 
vanized ground  rod,  not  less  than  one  inch  in  diameter,  driven 
eight  feet  into  the  ground. 


FIQ.  276.    MODEL  1  FORM  A 
LIGHTNINO  ARRESTERS 


372  GENERAL  RAILWAY  SIGNAL  COMPANY 

to  VOLTS  LIMITING  RESISTANCE  IS  OHMS 

I  AMPERE  RANGE 


r 


^J*/W (t$^ 


APPROXIMATELY  K>  FECT- 
FIG.  277.     CIRCUIT  FOR  TESTING  RESISTANCE  OP  GROUNDS 

NOTE. —  Several  readings  should  be  made  and  the  average  taken.  The 
resistance  should  then  be  computed  by  dividing  the  voltage  reading  by  the 
current. 

The  limiting  resistance  used  in  making  the  test  may  merely  be  a  unit  of 
such  resistance  as  to  protect  the  instruments,  it  being  recommended,  how- 
ever, that-  a  variable  resistance  be  used  if  available.  If  a  voltage  higher 
than  that  indicated  is  used,  the  range  of  the  voltmeter  and  the  resistance 
unit  employed  will  have  to  be  increased  accordingly. 

« 

PULLEYS  AND   GEARS 

When  it  is  desired  to  secure  single  reduction  or  increase  of 
speed  by  means  of  belting,  the  speed  at  which  each  shaft 
should  run  and  the  diameter  of  one  pulley  being  known, 
multiply  the  diameter  of  the  known  pulley  by  the  speed  in 
revolutions  per  minute  of  its  shaft  and  divide  this  product  by 
the  speed  in  revolutions  per  minute  of  the  second  shaft;  the 
result  is  the  desired  diameter  of  the  second  pulley. 

When  the  diameter   of  both  pulleys  and  the  speed  of  one 
shaft  is  known,  multiply  the  speed  of  that  shaft  by  the  diame- 
ter of  its  pulley  and  divide  this  product  by  the  diameter  of 
the  pulley  on  the  other  shaft;  the  result  is  the  speed  at  which 
the  second  shaft  will  be  run. 
Let  D  =  diameter  of  driving  pulley. 
d  =  diameter  of  driven  pulley. 

S  =  number  of  revolutions  per  minute  of  driving  shaft, 
s  =  number  of  revolutions  per  minute  of  driven  shaft. 

Then  the  above  may  be  expressed  by  the  following  formula : 

DxS 


Where  a  counter-shaft  is  used,  to  obtain  either  size  or  speed 
of  the  main  driving  or  driven  pulley,  calculate  as  above, 
between  the  known  end  of  the  transmission  and  the  counter- 
shaft and  then  repeat  this  calculation  between  the  counter- 
shaft and  tne  unknown  end. 

Gears  in  mesh  transmit  speeds  in  proportion  to  the  number 
of  teeth  they  contain.  Count  the  number  of  teeth  in  the  gear- 
ing and  substitute  this  quantity  for  the  diameter  of  the  pulleys 
mentioned  above,  in  order  to  obtain  the  number  of  teeth  to  be 
cut  in  unknown  gear  or  speed  of  the  second  shaft. 


ELECTRIC   INTERLOCKING   HANDBOOK 


373 


WIDTHS  OF    BELTING   PER  HORSE   POWER 

A  rule  commonly  used  for  determining  the  width  of  belting 
is  that  "single"  belt  will  transmit  1  H.  P.  for  each  inch  in 
width  at  a  speed  of  1,000  feet  per  minute.  If  the  speed  is 
greater  or  less  the  power  transmitted  is  correspondingly 
increased  or  decreased. 

The  rule  may  be  stated  as  follows : 
TT  p  _w  x  d  xrpm_wv 
3820        ~1000 
In  which  w  =  width  of  belt  in  inches. 

d  =  diameter  of  pulley  in  inches. 
v  =  velocity  of  belt  in  feet  per  minute. 
rpm=  revolutions  per  minute. 

This  is  based  on  a  working  tension  of  30  pounds  per  inch  of 
width  of  belt.  Many  writers  give  as  a  safe  practice  for  single 
belts  in  good  condition  a  working  tension  of  45  pounds  per 
inch  of  width,  which  formula  gives  a  permissible  increase  in 
transmitted  horse  power  of  50  per  cent,  over  the  formula 
TT  T>  _wxdxrpm 

H'^ 3820~ 

For  "double"  belts  of  average  thickness,  the  transmitting 
efficiency  is  considered  as  10  to  7  compared  to  the  single  belt- 
ing discussed  above. 

These  formulas  are  based  on  the  supposition  that  the  arc  of 
contact  between  belt  and  pulley  is  180  degrees.  For  other  arcs 
the  transmitting  power  is  approximately  proportional  to  the 
ratio  of  the  degrees  of  arc  of  contact  to  180  degrees. 


TABLE    FOR   DETERMINING   WIDTH   OF   BELTING 


Speed  in 
Feet  per 
Minute 

WIDTH  OP  BELT  IN  INCHES 

2 

3 

4 

5 

6 

H.  P. 

H.  P. 

H.  P. 

H.  P. 

H.  P. 

500 

1 

1.5 

2 

2.5 

3 

1000 

2 

3 

4 

5 

6 

1500 

3 

4.5 

6 

7.5 

9 

2000 

4 

6 

8 

10 

12 

2500 

5 

7.5 

10 

12.5 

15 

3000 

6 

9 

12 

15 

18 

3500 

7 

10.5 

14 

17.5 

21 

4000 

8 

12 

16 

20 

24 

4500 

9 

13.5 

18 

22.5 

27 

5000 

10 

15 

20 

25 

30 

NOTE.—  Based  on  the  formula  H.  P.= 


In  running,  the  upper  side  of  the  belt  should  sag  downward, 
the  belt  will  then  be  in  contact  with  more  than  half  the  cir- 


374 


GENERAL  RAILWAY  SIGNAL  COMPANY 


cumference  of  the  pulley,  and  the  power  increased  in  the  pro- 
portion referred  to  in  the  preceding  paragraph.  Best  results 
are  secured  by  running  belt  just  tight  enough  to  prevent 
slipping  at  normal  load. 


PAINTING 
EXTRACTS  FROM  R.  S.  A.  SPECIFICATIONS  FOR  ELECTRIC 

INTERLOCKING  (1910) 
800.  PAINT 

Field  work. 

(6)  Surfaces  covered  with  rust,  grease,  dirt,  or  other 
foreign  substances,  shall  be  thoroughly  cleaned  before 
paint  or  oil  is  applied. 

(c)  Paint  shall  not  be  applied  to  outside  surfaces  in 
freezing  weather,  nor  to  wet  surfaces,  nor  until  previous 
coating  has  thoroughly  dried. 

(d)  Finishing  coats  shall  not  be  applied  until  after  the 
expiration  of  forty-eight   (48)   hours  after  the  previous 
coating  has  been  applied. 

(e)  Paints  mixed  on  the  ground  shall  be  applied  within 
three  (3)  hours  after  the  pigment  and  oil  are  mixed. 

(/)  Priming  coats  shall  be  applied  as  soon  as  is  con- 
sistent with  the  progress  of  the  work. 

(gf)  Second  coat  shall  be  applied  in  sufficient  time  for 
the  third  coat  to  be  applied  and  dry  when  the  installation 
is  completed. 

810.  IRON  WORK 

(a)  Iron  work  (except  machine,  tie  plates,  and  iron 
foundation  piers)  not  galvanized  shall  be  painted  one  (1) 
coat  of  red  lead  and  raw  linseed  oil  and  two  (2)  finishing 
coats. 


AMOUNT   OF   PAINT   REQUIRED   PER    1000   FEET   OF 
TRUNKING   AND   CAPPING 


Size  of  Trunking 
Inches 

Size  of  Capping 
Inches 

Gallons  (two  coats) 

2x    3 

1x3 

4 

3x    4 

iy4x  4 

5V2 

4x7 

1V2X     7 

9 

4x  10 

2     xlO 

11 

NOTE. —  The  covering  capacity  of  paint  depends  largely  on  the  condition 
of  the  surface  being  finished,  the  handling  of  the  goods  by  the  painter,  and 
the  temperature  of  the  surface  painted.  The  above  figures  are  based  on 
average  working  conditions. 


ELECTRIC   INTERLOCKING  HANDBOOK 


375 


RAIL  SECTIONS 


A.  R.  A.  RAILS  — TYPE  "A" 


Weight 

per 

A 

B 

c 

D 

E 

F 

G 

Yard 

Lbs. 

In. 

In. 

In. 

In. 

In. 

In. 

In. 

60 

4y2 

22%4 

"Ho 

!15/64 

2V4 

15/32 

4 

70 

48/4 

2y2 

2%2 

1!%2 

2% 

y2 

4y4 

80 

5Vs 

22%2 

^32 

1%« 

2V2 

8%4 

4% 

90 

5% 

3%2 

1 

l15/32 

2%e 

%e 

5y8 

100 

6 

3% 

IVie 

1%6 

2»/4 

%« 

5y2 

A.  R.  A.  RAILS— TYPE  "B" 


Weight ; 
per 
Yard 


Lbs. 


In. 


60 
70 
80 
90 
100 


In. 


B%4 


In. 


In. 


2% 


l15/32 


85/04 


%e 


In. 


4%4 


5%4 


A.  S.  C.  E.  RAILS 


Weight 

per 

A 

B 

C 

D 

E 

F 

G 

Yard 

Lbs. 

In. 

In. 

In. 

In. 

*In. 

In. 

In. 

55 

4He 

2i%* 

28/32 

1^64 

2y4 

15/82 

4%o 

60 

4V4 

2"/64 

*%4 

l%a 

2% 

8y64 

4y4 

65 

4%6 

2% 

2%3 

1%2 

218/82 

y2 

4%6 

70 

4% 

2i%2 

18Ao 

1^3 

2^6 

8%4 

4% 

75 

4i%o 

2»%4 

2%2 

12%4 

2i%2 

1%2 

4i3Ae 

80 

5 

2% 

% 

1% 

2y2 

8%4 

5 

85 

5%6 

28/4 

57/64 

18%4 

2%o 

%e 

5%6 

90 

5% 

25%4 

5%4 

lle/32 

2% 

%6 

58/8 

95 

5%a 

2«%4 

15/ie 

l*Vfl4 

2iHe 

%0 

5%o 

100 

58/4 

3%4 

8%2 

1*%4 

2% 

%e 

5% 

110 

ey8 

3iy82 

1 

125/82 

2% 

8%4 

6% 

376 


GENERAL  RAILWAY  SIGNAL  COMPANY 


TABLE   OF   TURNOUTS   FROM   STRAIGHT   TRACK 
GAUGE,  4  FEET,  8^2  INCHES.     THROW  OF  SWITCH,  5  INCHES 


FIG.  281 


Frog 
Num- 
ber 

Frog 
Angle 
FPE 

Length 
Point 
of  Frog 
to  Toe 
PD 

Length 
Point 
of  Frog 
to  Heel 
PE 

Length 
of 
Switch 
Rail 
AC 

Switch 
Angle 
BAC  = 
TOG 

Radius 
of 
Center 
Line 
OC-i  ga 

Degree 
of 
Lead 
Curve 

Lead-Dist. 
Actual 
Point  of 
Switch 
Rail  to 
Actual 
Point  of 
Frog  AB 

in 

t     « 

£  S 

£    « 

ill 

e 

§?    3     « 
Q     3     £ 

«l 

fc 

6 

9-31-38 

4-  0 

7-  0 

11-0 

2-36-19 

265.39 

21-43-04 

47.98 

7 

8-10-16 

4-  5 

8-  1 

16-6 

1-44-11 

362.08 

15-52-29 

62.10 

8 

7-09-10 

4-  9 

8-  9 

16-6 

1-44-11 

487.48 

11-46-27 

67.98 

9 

6-21-35 

6-  0 

10-  0 

16-6 

1-44-11 

605.18 

9-28-42 

72.28 

9V2 

6-01-32 

6-  0 

10-  0 

16-6 

1-44-11 

695.45 

8-14-45 

75.71 

10 

5-43-29 

6-  0 

10-  6 

16-6 

1-44-11 

790.25 

7-15-18 

77.93 

11 

5-12-18 

6-  0 

11-  6 

22-0 

1-18-  8 

922.65 

6-12-47 

94.31 

12 

4-46-19 

6-  5 

12-  1 

22-0 

1-18-  8 

1098.73 

5-12-59 

100.80 

15 

3-49-06 

7-  8 

14-10 

33-0 

0-52-  5 

1744.38 

3-17-01 

133.28 

16 

3-34-47 

8-  0 

16-  0 

33-0 

0-52-  5 

1993.24 

2-52-59 

137.57 

18 

3-10-56 

8-10 

17-  8 

33-0 

0-52-  5 

2546.31 

2-14-31 

146.51 

20 

2-51-51 

9-  8 

19-  4 

33-0 

0-52-  5 

3257.26 

1-45-32 

157.42 

24 

2-23-13 

11-  4 

23-  2 

33-0 

0-52-  5 

4886.16 

1-10-21 

177.22 

Above  from  table  by  American  Railway  Engineering  Association. 


ELECTRIC  INTERLOCKING  HANDBOOK 


377 


TABLE  OF   CROSSOVERS 
GAUGE,  4  FEET,  8%  INCHES.     THROW  OF  SWITCH,  5  INCHES 


lead  —  >je  K  ->j<  Lead  > 

T"  '      "^  —  1            ' 

Track  Centers       *""*  •^•^^"^"l1**11*-**. 

FIG.  282 


DISTANCE  (A)  BETWEEN  FROG  POINTS  FOR  TRACK 

Fro 

LEAD 

CENTERS  BELOW 

Number 

11' 

12' 

13' 

14' 

15' 

16' 

Feet 

Feet 

Feet 

Feet 

Feet 

Feet 

Feet 

6 

47.98 

9.5 

15.5 

21.5 

27.5 

33.5 

39.5 

7 

62.10 

11.1 

18.1 

25.1 

32.1 

39.1 

46.1 

8 

67.98 

12.7 

20.7 

28.7 

36.7 

44.7 

52.7 

9 

72.28 

14.2 

23.2 

32.2 

41.2 

50.2 

59.2 

m 

75.71 

15.0 

24.5 

34.0 

43.5 

53.0 

62.5 

10 

77.93 

15.8 

25.8 

35.8 

45.8 

55.8 

65.8 

11 

94.31 

17.4 

28.4 

39.4 

50.4 

61.4 

72.4 

12 

100.80 

19.0 

31.0 

43.0 

55.0 

67.0 

79.0 

15 

133.28 

23.8 

38.8 

53.8 

68.8 

83.8 

98.8 

16 

137.57 

25.3 

41.3 

57.3 

73.3 

89.3 

105.3 

18 

146.51 

28.4 

46.4 

64.4 

82.4 

100.4 

118.4 

20 

157.42 

31.6 

51.6 

71.6 

91.6 

111.6 

131.6 

24 

177.22 

38.0 

62.0 

86.0 

110.0 

134.0 

158.0 

TOTAL  LENGTH  OF  CROSSOVER  FOR  TRACK  CENTERS  BELOW 

Frog 
Number 

11' 

12' 

13' 

14' 

15' 

16' 

Feet 

Feet 

Feet 

Feet 

Feet 

Feet 

6 

105.5 

111.5 

117.5 

123.5 

129.5 

135.5 

7 

135.3 

142.3 

149.3 

156.3 

163.3 

170.3 

8 

148.7 

156.7 

164.7 

172.7 

180.7 

188.7 

9 

158.8 

167.8 

176.8 

185.8 

194.8 

203.8 

m 

166.4 

175.9 

185.4 

194.9 

204.4 

213.9 

10 

171.7 

181.7 

191.7 

201.7 

211.7 

221.7 

11 

206.0 

217.0 

228.0 

239.0 

250.0 

261.0 

12 

220.6 

232.6 

244.6 

256.6 

268.6 

280.6 

15 

290.4 

305.4 

320.4 

335.4 

350.4 

365.4 

16 

300.4 

316.4 

332.4 

348.4 

364.4 

380.4 

18 

321.4 

339.4 

357.4 

375.4 

393.4 

411.4 

20 

346.4 

366.4 

386.4 

406.4 

426.4 

446.4 

24 

392.4 

416.4 

440.4 

464.4 

488.4 

512.4 

NOTE. —  Distance  (A)  between  frog  points  based  on  formula 
Distance  =  (track  centers  —  2  x  gauge)  x  frog  number. 


378 


GENERAL  RAILWAY  SIGNAL  COMPANY 


Per  Track 

BOND   WIRES   AND   CHANNEL   PINS 

Diagram  below  gives  the  actual  number  of  bond 
fires    and    channel   pins    required    for  bonding 
ingle  track  road   (2  rails)    for  distances   up  to 
,000   feet.     To  this  should  be  added  25  bond 
fires  and  50  channel  pins  for  each  switch,  and  to 
tie  total  5  per  cent,  added  to  cover  loss. 

Per  TracK 

704     I4QB 
640    1230 

•        K  -    •  '     i 

—                 s  v 

2  C      o-—    v 
gS     coc  t 

<650    825 

| 

j 

A 

1500    750 

J 

y 

f 

i 

f 

y 

1350     675 

/ 

J 

f 

A 

A 

I    m  . 

/ 

y 

1200     600 

f, 

J 

y 

A 

1 

^ 

f 

/ 

f 

(050    525 

\ 

, 

3 

sT 

£ 

A 

f 

< 

900    450 

t 

•\ 

J 

J 

>s 

J 

V 

J 

, 

i 

750    375 

J 

1 

J 

J 

J 

J 

A 

J 

600    300 

J 

/ 

. 

f 

J 

. 

A 

J 

t 

450    225 

y 

/ 

t 

y" 

^  / 

y 

300     150 

v 

(A 

I 

x 

JJ 

1 

150     75 

I 

J 

0        0 

0         1000       2000       3000     4000      5000 
5 

6000  Ft  of  Ttecl 
80 

FIG.  283 


ELECTRIC  INTERLOCKING   HANDBOOK 


379 


TWIST   DRILL  AND   STEEL   WIRE   GAUGE 


No. 

Size 

No. 

Size 

No. 

Size 

No. 

Size 

No. 

Size 

Inch 

Inch 

Inch 

Inch 

Inch 

1 

.2280 

13 

.1850 

25 

.1495 

37 

.1040 

49 

.0730 

2 

.2210 

14 

.1820 

26 

.1470 

38 

.1015 

50 

.0700 

3 

.2130 

15 

.1800 

27 

.1440 

39 

.0995 

51 

.0670 

4 

.2090 

16 

.1770 

28 

.1405 

40 

.0980 

52 

.0635 

5 

.2055 

17 

.1730 

29 

.1360 

41 

.0960 

53 

.0595 

6 

.2040 

18 

.1695 

30 

.1285 

42 

.0935 

54 

.0550 

7 

.2010 

19 

.1660 

31 

.1200 

43 

.0890 

55 

.0520 

8 

.1990 

20 

.1610 

32 

.1160 

44 

.0860 

56 

.0465 

9 

.1960 

21 

.1590 

33 

.1130 

45 

.0820 

57 

.0430 

10 

.1935 

22 

.1570 

34 

.1110 

46 

.0810 

58 

.0420 

11 

.1910 

23 

.1540 

35 

.1100 

47 

.0785 

59 

.0410 

12 

.1890 

24 

.1520 

36 

.1065 

48 

.0760 

60 

.0400 

Reprinted  by  permission  from  Kent's  "Mechanical  Engineers'  Pocket  Book." 


STUBS'  STEEL   WIRE   GAUGE 


"Mr* 

Size 

"Mr* 

Size 

*Wr» 

Size 

*w/\ 

Size 

TVT/\ 

Size 

-NO. 

Inch 

JNO. 

Inch 

INO. 

Inch 

INO. 

Inch 

i\O. 

Inch 

Z 

.413 

D 

.246 

19 

.164 

41 

.095 

63 

.036 

Y 

.404 

C 

.242 

20 

.161 

42 

.092 

64 

.035 

X 

.397 

B 

.238 

21 

.157 

43 

.088 

65 

.033 

w 

.386 

A 

.234 

22 

.155 

44 

.085 

66 

.032 

V 

.377 

1 

.227 

23 

.153" 

45 

.081 

67 

.031 

u 

.368 

2 

.219 

24 

.151 

46 

.079 

68 

.030 

T 

.358 

3 

.212 

25 

.148 

47 

.077 

69 

.029 

s 

.348 

4 

.207 

26 

.146 

48 

.075 

70 

.027 

R 

.339 

5 

.204 

27 

.143 

49 

.072 

71 

.026 

Q 

.332 

6 

.201 

28 

.139 

50 

.069 

72 

.024 

p 

.323 

7 

.199 

29 

.134 

51 

.066 

73 

.023 

O 

.316 

8 

.197 

30 

.127 

52 

.063 

74 

.022 

N 

.302 

9 

.194 

31 

.120 

53 

.058 

75 

.020 

M 

.295 

10 

.191 

32 

.115 

54 

.055 

76 

.018 

L 

.290 

11 

.188 

33 

.112 

55 

.050 

77 

.016 

K 

.281 

12 

.185 

34 

.110 

56 

.045 

78 

.015 

J 

.277 

13 

.182 

35 

.108 

57 

.042 

79 

.014 

I 

.272 

14 

.180 

36 

.106 

58 

.041 

80 

.013 

H 

.266 

15 

.178 

37 

.103 

59 

.040 

G 

.261 

16 

.175 

38 

.101 

60 

.039 

F 

.257 

17 

.172 

39 

.099 

61 

.038 

E 

.250 

18 

.168 

40 

.097 

62 

.037 

The  Stubs'  Steel  Wire  Gauge  is  used  in  measuring  drawn  steel  wire  or 
drill  rods  of  Stubs'  make,  aud  is  also  used  by  many  makers  of  American 
drill  rods. 

Reprinted  by  permission  from  Kent's  "Mechanical  Engineers'  Pocket  Book." 


380 


GENERAL  RAILWAY  SIGNAL  COMPANY 


STANDARD   SCREW   THREADS,  NUTS,  BOLT   AND   LAG   HEADS 
U.  S.  STANDARD 


Dlam.  of 
Screw 

Inch 

Threads 
per  Inch 

Dlam.  of 
Core 

Inch 

Width  of 
Flat 

Inch 

Outside 
Dlam. 
Hex.  Head 
Inch 

Inside 
Diam. 
Hex.  or 
Sq.Head 
Inch 

Diago- 
nal Sq. 
Head 
Inch 

Height 
of  Head 

Inch 

y* 

20 

.185 

0062 

%a 

y2 

M4« 

% 

9U 

18 

.240 

.0070 

*H« 

ia/82 

18Ae 

>«4 

% 

16 

.294 

.0078 

2%2 

1^6 

8y32 

**• 

tte 

14 

.344 

.0089 

*8/48 

2%2 

1%« 

2%4 

y2 

13 

.400 

.0096 

1 

% 

1% 

7/16 

%6 

12 

.454 

.0104 

1%4 

«y32 

1%6 

8ye4 

% 

11 

.507 

.0113 

!7/82 

IHe 

iy2 

17/82 

% 

10 

.620 

.0125 

Iftf 

iy* 

1% 

% 

% 

9 

.731 

.0140 

1% 

IT/ie 

2y82 

28/32 

1 

8 

.837 

.0156 

1% 

1% 

2%a 

18Ae 

1% 

7 

.940 

.0180 

2%2 

1!%6 

2y2 

2%2 

iy* 

7 

.065 

.0180 

2%e 

2 

22%2 

1 

1% 

6 

.160 

.0210 

2y2 

2«Ae 

3He 

1%2 

iy2 

6 

.284 

.0210 

2% 

2% 

3% 

1%6 

1% 

5% 

.389 

.0227 

2i%9 

2%e 

3% 

1%2 

i% 

5 

.490 

.0250 

3«Ae 

2% 

32%2 

1% 

1% 

5 

.615 

.0250 

3i%2 

2i%6 

4%6 

U%2 

2 

4y2 

.712 

.0280 

3% 

3y8 

4%e 

1%6 

2^4 

4y2 

.962 

.0280 

4^6 

3y2 

48y82 

18/4 

2y2 

4 

2.175 

.0310 

4y2 

3% 

5y2 

l1BAe 

2% 

4 

2.425 

.0310 

429/32 

4y4 

6 

2y8 

3 

3y2 

2.628 

.0357 

5% 

4% 

6%« 

2%6 

3% 

3y2 

2.878 

.0357 

5% 

5 

m 

2y2 

3% 

3H 

3.100 

.0384 

6%4 

5% 

7% 

2i^4o 

3% 

3 

3.317 

.0410 

6% 

5«/4 

8%6 

2% 

4 

3 

3.566 

.0410 

7%4 

ey8 

8H46 

3He 

*& 

27/8 

3.798 

.0435 

7y2 

ey2 

9y4 

sy4 

4y2 

2% 

4.027 

.0460 

7»%a 

6% 

9»/4 

3%e 

4% 

2% 

4.255 

.0480 

8% 

7y4 

10%2 

3% 

5 

2tt 

4.480 

.0500 

8i3/i8 

7% 

101%6 

3i%e 

5V4 

2y2 

4.730 

.0500 

9^4 

8 

11% 

4 

5% 

2% 

4.953 

.0526 

9iVi6 

8% 

112»/32 

48Ae 

53/4 

2% 

5.203 

.0526 

ioy8 

8»/4 

12%6 

48/8 

6 

2y4 

5.423 

.0555 

10%6 

9y8 

12%« 

4%6 

NOTE. —  Threads  have  an  angle  of  60  degrees,  with  flat  tops  and  bottoms. 


ELECTRIC   INTERLOCKING  HANDBOOK 


381 


STANDARD    MACHINE    SCREWS 


Diam. 

Diam.  of  Diam.  of 

LENGTHS 

No. 

Threads 
per 

of  Body 

of  Flat 
Head 

Round 
Head 

Filister 
Head 

Clear- 
ance 

From 

To 

Inch 

Inch 

Inch 

Inch 

Inch 

Inch 

2 

56 

.0842 

.1631 

.1544 

.1332 

%« 

% 

41-43 

4 

32,  36,  40 

.1105 

.2158 

.2028 

.1747 

%6 

% 

30-32 

6 

30,32 

.1368 

.2684 

.2512 

.2175 

%8 

1 

27-28 

8 

30,32 

.1631 

.3210 

.2936 

.2610 

% 

1% 

17-18 

10 

24,  30,  32 

.1894 

.3737 

.3480 

.3035 

9i 

1% 

11-  8 

12 

20,24 

.2158 

.4263 

.3922 

.3445 

% 

1% 

2-  1 

14 

20,24 

.2421 

.4790 

.4364 

.3885 

% 

2 

V4 

NOTE. —  Lengths  vary  by  16ths  from  9io  to  %,  by  8ths  from  %  to  1%,  by 
4ths  from  1%  to  2. 


STANDARD    DIMENSIONS    OF    WROUGHT-IRON    WELDED    PIPE 
BRIGGS'  STANDARD 


Nominal 
Inside 
Diam. 

Actual 
Outside 
Diam. 

Thickness 
of  Metal 

Length  of 
Pipe  per 
Sq.  Ft. 
Outside 
Surface 

Internal 
Area 

Weight  of 
Pipe  per 
Lineal  Foot 

Number  of 
Threads 
per  Inch 

Ins. 

Ins. 

Ins. 

Ft. 

Sq.  In. 

Lbs. 

No. 

14 

.540 

.088 

7.075 

.104 

.42 

18 

% 

.675 

.091 

5.658 

.191 

.56 

18 

% 

.840 

.109 

4.547 

.304 

.84 

14 

% 

1.050 

.113 

3.638 

.533 

1.12 

14 

l 

1.315 

.134 

2.904 

.861 

1.67 

11% 

m 

1.660 

.140 

2.301 

1.496 

2.24 

11% 

1% 

1.900 

.145 

2.010 

2.036 

2.68 

11% 

2 

2.375 

.154 

1.608 

3.356 

3.61 

11% 

2% 

2.875 

.204 

1.329 

4.780 

5.74 

8 

3 

3.500 

.217 

1.091 

7.383 

7.54 

8 

3% 

4.000 

.226 

.955 

9.887 

9.00 

8 

4 

4.500 

.237 

.849 

12.730 

10.66 

8 

41/2 

5.000 

.246 

.764 

15.961 

12.34 

8 

5 

5.563 

.259 

.687 

19.986 

14.50 

8 

6 

6.625 

.280 

.577 

28.890 

18.76 

8 

7 

7.625 

.301 

.501 

38.738 

23.27 

8 

8 

8.625 

.322 

.443 

50.027 

28.18 

8 

9 

9.625 

.344 

.397 

62.730 

33.70 

8 

10 

10.75 

.366 

.355 

78.823 

40.06 

8 

382 


GENERAL  RAILWAY  SIGNAL  COMPANY 


SQUARE    HEAD    LAG   SCREWS 


Diameter 
in 
Inches 

%6 

% 

%6 

y2 

%6 

% 

8/4 

% 

1 

Length 
in 
Inches 

Average  Weight  per  Hundred 

Lbs.      Lbs. 

Lbs. 

Lbs. 

Lbs. 

Lbs. 

Lbs. 

Lbs. 

Lbs. 

1% 

!8/4 

2 

2V4 

2Y2 

3 

4.2 
4.7 
5.2 
5.7 
6.2 
7.2 

6.5 
7.1 

7.7 
8.4 
9.2 
10.6 

9.2 
10.0 
10.9 
11.8 
12.7 
14.6 

13.0 
13.8 
14.9 
16.1 
17.4 
19.0 

23.0 
24.5 
26.0 
29.2 

24.8 
27.3 
29.0 
32.9 

43.0 
48.3 

75.0 

B% 

8.2 

12.0 

16.6 

21.5 

32.5 

36.9 

53.8 

78.5 

90 

4 

9.2 

13.5 

18.8 

24.0 

35.9 

41.0 

59.6 

82.0 

99 

4V2 

10.2 

15.0 

20.7 

26.5 

39.3 

44.9 

65.5 

86.0 

108 

5 

11.3 

16.5 

22.8 

29.0 

42.7 

48.8 

71.5 

90.0 

118 

5% 

12.4 

18.0 

24.9 

31.5 

46.1 

52.7 

77.5 

98.0 

128 

6 

13.5 

19.5 

27.0 

34.0 

49.5 

56.6 

83.5 

106.0 

138 

NOTE. —  For  dimensions  of  lag  screw  heads,  see  page  380. 


COMMON   WIRE    NAILS 


Size 

Length 
in 
Inches 

Diameter 
in 
Inches 

Approx. 
Number  to 
Lb. 

Approx. 
Lbs.  per 
1000 

2D 

1 

.072 

876 

1.14 

3D 

1% 

.080 

568 

1.76 

4D 

1% 

.100 

316 

3.16 

5D 

1% 

.100 

271 

3.69 

6D 

2 

.113 

181 

5.53 

7D 

21/4 

.113 

161 

6.21 

8D 

2V2 

.131 

106 

9.43 

9D 

2% 

.131 

96 

10.4 

10D 

3 

.148 

69 

14.5 

12D 

Stt 

.148 

63 

15.9 

16D 

3V2 

.162 

49 

20.4 

20D 

4 

.192 

31 

32.3 

30D 

4% 

.207 

24 

41.7 

40D 

5 

.225 

18 

55.6 

SOD 

5Va 

.244 

14 

71.4 

60D 

6 

.263 

11 

90.9 

ELECTRIC   INTERLOCKING  HANDBOOK 


383 


TABLE   OF   BOARD    MEASURE 


Size 

Length  in  Feet 

10 

12 

14 

16 

18 

Feet  Board  Measure 

1x2 

1% 

2 

2% 

2% 

3 

1  x4 

3% 

4 

4% 

5% 

6 

1  x6 

5 

6 

7 

8 

9 

1x8 

6% 

8 

9% 

10% 

12 

1x10 

8% 

10 

11% 

131/8 

15 

1x12 

10 

12 

14 

16 

18 

1  x  14 

11  73 

14 

16% 

18% 

21 

2x4 

6% 

8 

9% 

10% 

12 

2x6 

10 

12 

14 

16 

18 

2x8 

131/3 

16 

18% 

211/8 

24 

2x10 

16% 

20 

23V3 

26% 

30 

2x12 

20 

24 

28 

32 

36 

2x14 

231/3 

28 

32% 

37% 

42 

3x8 

20 

24 

28 

32 

36 

3x10 

25 

30 

35 

40 

45 

3x12 

30 

36 

42 

48 

54 

3x14 

35 

42 

49 

56 

63 

4x4 

131/3 

16 

18% 

21% 

24 

4x6 

20 

24 

28 

32 

36 

4x8 

26% 

32 

37% 

42% 

48 

4x  10 

33% 

40 

46% 

53% 

60 

4x12 

40 

48 

56 

64 

72 

4x14 

46% 

56 

65% 

74% 

84 

NOTE. —  Length   in   feet  X  width   in    feet  X  thickness  in  inches— number 
of  feet  board  measure.      (1  cu.  ft.  of  lumber  =  12  board  feet.) 


384 


GENERAL  RAILWAY  SIGNAL  COMPANY 


BAUME'S   HYDROMETER   AND    SPECIFIC   GRAVITIES 
COMPARED 


Liquids 

Liquids 

Liquids 

Liquids 

Degrees 
Baume 

Heavier 
than 
Water, 

Lighter 
than 
Water, 

Degrees 
Baume 

Heavier 
than 
Water, 

Lighter 
than 
Water, 

Sp.  Gr. 

Sp.  Gr. 

Sp.  Gr. 

Sp.  Gr. 

0.0 

.000 

28.0 

1.239 

0.886 

1.0 

.007 

29.0 

1.250 

0.881 

2.0 

.014 

30.0 

1.261 

0.875 

3.0 

.021 

31.0 

1.272 

0.870 

4.0 

.028 

32.0 

1.283 

0.864 

5.0 

.036 

33.0 

1.295 

0.859 

6.0 

.043 

34.0 

1.306 

0.854 

7.0 

.051 



35.0 

1.318 

0.849 

8.0 

1.058 

36.0 

1.330 

0.843 

9.0 

1.066 

37.0 

1.343 

0.838 

10.0 

1.074 

1.000 

38.0 

1.355 

0.833 

11.0 

1.082 

0.993 

39.0 

1.368 

0.828 

12.0 

1.090 

0.986 

40.0 

1.381 

0.824 

13.0 

1.099 

0.979 

41.0 

1.394 

0.819 

14.0 

1.107 

0.972 

42.0 

1.408 

0.814 

15.0 

1.115 

0.966 

44.0 

1.436 

0.805 

16.0 

1.124 

0.959 

46.0 

.465 

0.796 

17.0 

1.133 

0.952 

48.0 

.495 

0.787 

18.0 

1.142 

0.946 

50.0 

.526 

0.778 

19.0 

1.151 

0.940 

52.0 

.559 

0.769 

20.0 

.160 

0.933 

54.0 

.593 

0.761 

21.0 

.169 

0.927 

56.0 

.629 

0.753 

22.0 

.179 

0.921 

58.0 

.667 

0.745 

23.0 

.189 

0.915 

60.0 

.706 

0.737 

24.0 

.198 

0.909 

65.0 

.813 

0.718 

25.0 

.208 

0.903 

70.0 

.933 

0.700 

26.0 

.219 

0.897 

75.0 

2.071 

0.683 

27.0 

.229 

0.892 

Reprinted  by  permission  from  "Kent's  Mechanical  Engineers'  Pocket  Book." 


ELECTRIC  INTERLOCKING   HANDBOOK 


385 


SPECIFIC   GRAVITY   OF   LIQUIDS   AT   60   DEGREES  FAHR. 


Acid,  Muriatic  

1.200 

Oil,  Olive,    .... 

.   0.92 

Acid,  Nitric,     

1.217 

Oil,  Palm  

.  0.97 

Acid,  Sulphuric,  

1.849 

Oil,  Petroleum,   .    . 

.   0.78  toO 

88 

Alcohol,  pure,  

0.794 

Oil,  Rape,    .... 

.   0.92 

Alcohol,  95  per  cent.,      .    . 

0.816 

Oil,  Turpentine,  .    . 

.  0.87 

Alcohol,  50  per  cent.,      .    . 

0.934 

Oil,  Whale,      .    .    . 

.   0.92 

Ammonia,  27  .9  per  cent.,  . 

0.891 

Tar,     

.   1. 

Bromide,  

2.97 

Vinegar,     .... 

.    .1.08 

Carbon,  disulphide,     .    .    . 

1.26 

Water,   

.    1. 

Ether,  Sulphuric  

0.72 

Water,  Sea,      .    .    . 

.    1.026  to  1 

.03 

Oil,  Linseed,     

0.94 

Reprinted  by  permission  from  "Kent's  Mechanical  Engineers'  Pocket  Book." 


SPECIFIC   GRAVITY   AND   WEIGHT   OF   WOOD 


Specific 
Gravity 

Weight  per 
Cubic  Foot, 
Pounds 

Specific 
Gravity 

Weight  per  I 
Cubic  Foot, 
Pounds 

Avge. 

« 

Avge. 

Alder  

0.56  to  0.80  0.68 

42 

Hornbeam, 

0.76              0.76 

47 

Apple  

0.73to0.790.76 

47 

Juniper,   .    . 

0.56              0.56 

35 

Ash,     .... 

0.60to0.840.72 

45 

Larch,  .    .    . 

0.56              056 

35 

Bamboo,      .    . 

0.31  toO.  40  0.35 

22 

Lignum  vitse 

0.65  to  1.33  1.00 

62 

Beech,     .    .    . 

0.62  to  0.85  0.73 

46 

Linden,    .    . 

0.604 

37 

Birch,  .... 

0.56  to  0.74  0.65 

41 

Locust,    .    . 

0.728 

46 

Box,     .... 

0.91  to  1.33  1.12 

70 

Mahogany,  . 

0.56  to  1.06  0.81 

51 

Cedar  

0.49  to  0.75  0.62 

39 

Maple,.    .    . 

0.57  to  0.79  0.68 

42 

Cherry,    .    .    . 

0.61  to  0.72  0.66 

41 

Mulberry,     . 

0.56  to  0.90  0.73 

46 

Chestnut,    .    . 

0.46  to  0.66  0.66 

35 

Oak,  Live,  . 

0.96  to  1.26  1.11 

69 

Cork  

0.24              0.24 

15 

Oak,  White, 

0.69  to  0.86  0.77 

48 

Cypress,  .    .    , 

0.41to0.660.53 

33 

Oak,  Red,    . 

0.73  to  0.75  0.74 

46 

Dogwood,    .    . 

0.76              0.76 

47 

Pine,  White, 

0.35  to  0.55  0.45 

28 

Ebony,    .    .    . 

1.13  to  1.33  1.23 

76 

Pine.Yellow, 

0.46  to  0.76  0.61 

38 

Elm,     .... 

0.55  to  0.78  0.61 

38 

Poplar,     .    . 

0.38  to  0.58  0.48 

30 

Fir,  

0.48  to  0.70  0.59 

37 

Spruce,    .    . 

0.40  to  0.50  0.45 

28 

Gum,   .... 

0.84  to  1.00  0.92 

57 

Sycamore,   . 

0.59  to  0.62  0.60 

37 

Hackmatack,  . 

0.59              0.59 

37 

Teak,    .    .    . 

0.66  to  0.98  0.82 

51 

Hemlock,    .    . 

0.36to0.41  0.38 

24 

Walnut,   .    . 

0.50  to  0.67  0.58 

36 

Hickory,  .    .    . 

0.69  to  0.94  0.77 

48 

Willow,    .    . 

0.49  to  0.59  0.54 

34 

Holly  

0.76              0.76 

47 

Reprinted  by  permission  from  "Kent's  Mechanical  Engineers'  Pocket  Book." 


386 


GENERAL  RAILWAY  SIGNAL  COMPANY 


SPECIFIC   GRAVITY   AND   WEIGHT    OF   STONES,  BRICK, 
CEMENT,  ETC.     (Pure  Waters  1.00.) 


Sp.  Gr. 

Lb.  per  Cu.  Ft. 

Asphaltum,    

1.39 

87 

Brick,  Soft,    

1.6 

100 

Brick,  Common,   

1.79 

112 

Brick   Hard  . 

2  0 

125 

Brick  Pressed 

2  16 

135 

Brick,  Fire,    

2.24  to  2.  4 

140  to  150 

Brick   Sand-lime 

2  18 

136 

Brickwork  in  mortar,  

1.6 
1.79 

100 
112 

Cement,  American,  natural,    .... 
Cement,  Portland,    
Cement,  Portland,  loose,     

2.8    to  3.  2 
3.  05  to  3.  15 

92 

Cement,  Portland,  in  barrels,     .    .    . 
Clay 

1  92  to  2  4 

115 
120  to  150 

Concrete,    

1.92  to  2.  48 

120  to  155 

Earth  loose  . 

1   15  to  1  28 

72  to    80 

Earth  rammed, 

1  44  to  1  .76 

90  to  110 

Emery,  

4. 

250 

Glass                       .                .... 

25    to  2  75 

156  to  172 

Glass,  flint,    

2.88  to  3.  14 

180  to  196 

Gneiss    1 

2  56  to  2  72 

160  to  170 

Granite  ) 
Gravel,   
Gypsum,    
Hornblende  
Ice  
Lime,  quick,  in  bulk  
Limestone,     

1.6    to  1.92 
2.  08  to  2.  4 
3.2    to  3.  52 
0.88  to  0.92 
0.8    to  0.96 
2.30  to  2.  90 

100  to  120 
130  to  150 
200  to  220 
55  to    57 
50  to    60 
140  to  185 

Magnesia,  Carbonate,  
Marble  
Masonry,  dry  rubble,   
Masonry,  dressed,     

2.4 
2.  56  to  2.  88 
2.  24  to  2.  56 
2.24  to  2.  88 

150 
160  to  180 
140  to  160 
140  to  180 

Mica  

2.80 

175 

Mortar,  

.44  to  1  .6 
67  to  1.92 

90  to  100 
104  to  120 

Pitch,  

.15 

72 

Plaster  of  Paris,    
Quartz,  

.50  to  1.81 
.64 

93  to  113 
165 

Sand                                                .    . 

.44  to  1.76 

90  to  110 

Sand,  wet,  
Sandstone                          

.89  to  2.  07 
2.24  to  2.  4 

118  to  129 
140  to  150 

Slate                           

2.72  to  2.  88 

170  to  180 

Soapstone                   

2.65  to  2.  8 

166  to  175 

Stone  various,  

2.16  to  3.  4 

135  to  200 

Trap,  
Tile  

2.72  to  3.  4 
1.76  to  1.92 

170  to  200 
110  to  120 

Reprinted  by  permission  from  Kent's  "Mechanical  Engineers'  Pocket  Book.' 


ELECTRIC  INTERLOCKING  HANDBOOK 


387 


SPECIFIC   GRAVITY   AND   WEIGHT   OF   METALS 


Specific  Gravity. 
Range  According 
to  Several 

Specific  Grav- 
ity.  Approx. 
Mean  Value, 
used  in 

Weight 
per 
Cubic 
Foot 

Weight 
per 
Cubic 
Inch 

Authorities 

Oo,lculntion  of 
Weight 

Lbs. 

Lbs. 

Aluminum,         .... 

2.56    to    2.71 

2.67 

166.5 

0.0963 

Antimony  

6.66    to    6.86 

6.76 

421.6 

0.2439 

Bismuth,   

9.74    to    9.90 

9.82 

612.4 

0.3544 

Brass:  Copper-fZinc 

80         20  1 

rs.eo 

536.3 

0.3103 

70          30    1 
60         40    ( 
50         50  J 

7.8      to    8.6 

J  8.40 
1  8.36 
[8.20 

523.8 
521.3 
511.4 

0.3031 
0.3017 
0.2959 

(Cop.,  95  to  80  ) 
BronzelTin,      5  to  20  \ 

8.52    to    8.96 

8.853 

552. 

0.3195 

Cttdmiuin  • 

8.6      to    8.7 

8.65 

539. 

0.3121 

Calcium  

1.58 

1.58 

98.5 

0.0570 

Chromium,    

5.0 

5.0 

311.8 

0.1804 

Cobalt  

8.5      to    8.6 

8.55 

533.1 

0.3085 

Gold,  pure  

19.245  to  19.361 

19.258 

1200.9 

0  .6949 

Copper  .                   .    . 

8.69    to    8.92 

8.853 

552. 

0.3195 

Indium,     

22.38    to  23. 

22.38 

1396. 

0.8076 

Iron,  Cast,     

6.85    to    7.48 

7.218 

450. 

0.2604 

Iron,  Wrought,     .    .    . 

7.4      to    7.9 

7.70 

480. 

0.2779 

Lead  

11  .07    to  11  .44 

11.38 

709.7 

o.'Jioe 

Manganese,   

7.        to    8. 

8. 

499. 

0.2887 

Magnesium,  

1.69    to    1.75 

1.75 

109. 

0.0641 

{32° 

13.60    to  13.  62 

13.62 

849.3 

0.4915 

60° 

13.58 

13.58 

846.8 

0.4900 

212° 

13.37    to  13.  38 

13.38 

834.4 

0.4828 

Nickel  

8.  279  to    8.93 

8.8 

548.7 

0.3175 

Platinum  

20.33    to  22  .07 

21.5 

1347.0 

0.7758 

Potassium  

0.865 

0.865 

53.9 

0.0312 

Silver,    

10.474  to  10.511 

10.505 

655.1 

0.3791 

Sodium,     

0.97 

0.97 

60.5 

0.0350 

Steel 

7.69*  to    7.93?t 

7.854 

"489  .  6 

0  .  2834 

Tin,  '  

7.  291  to    7.409 

7.350 

458.3 

0.2652 

Titanium   . 

5.3 

5.3 

330.5 

0.1913 

Tungsten,  

17.         to  17.  6 

17.3 

1078.7 

0.6243 

Zinc 

6.86    to    7.20 

7.00 

436.5 

0.2526 

*  Hard  and  burned. 

t  Very  pure  and  soft.     The  sp.  gr.  decreases  as  the  carbon  is  increased. 

In  the  first  column  of  figures  the  lowest  are  usually  those  of  cast  metals, 
which  are  more  or  less  porous;  the  highest  are  of  metals  finely  rolled  or 
drawn  into  wire. 

Reprinted  by  permission  from  "Kent's  Mechanical  Engineers'  Pocket  Book." 


388  GENERAL  RAILWAY  SIGNAL  COMPANY 

TABLES   OF  WEIGHTS  AND   MEASURES 
LINEAR  MEASURE 

12      inches  (in.),    ....    =1  foot  (ft.) 

3  feet, =1  yard  (yd.) 

5. 5  yards, =lrod(rd.) 

40      rods, =-1  furlong  (fur.) 

8  furlongs, =1  mile  (mi.) 

1  mi. -8  fur.  =320  rods -1760  yd. -=5280  ft.  =  63, 360  in. 

SQUARE  MEASURE 

144      square  inches  (sq.  in.),    =1  square  foot  (sq.  ft.) 

9  square  feet,     ....    =1  square  yard  (sq.  yd.) 
30*4  square  yards,.    ...    =1  square  rod  (sq.  rd.) 

160      square  rods,    .    .    .    .    =  1  acre  (A) 

640      acres, =1  square  mile  (sq.  mi.) 

1  sq.  mi. -640  acres  =  102,400  sq.  rd.  =3,097,600  sq.  yd.= 
27,878,400  sq.  ft.  =4,014,489,600  sq.  in. 

CUBIC  MEASURE 

1,728      cubic  inches  (cu.  in.),    =1  cubic  foot  (cu.  ft.) 

27      cubic  feet, =1  cubic  yard  (cu.  yd.) 

128      cubic  feet, =lcord(cd.) 

24%  cubic  feet, =1  perch  (P.) 

1  cu.  yd.  =27  cu.  ft.  =46, 656  cu.  in. 

MEASURES  OP  ANGLES  OR  ARCS 

60      seconds  ("),     ....    =1  minute  (0 

60      minutes, =1  degree  (°) 

90      degrees, =1  right  angle  or  quadrant  (  D  ) 

360      degrees, =1  circle  (cir.) 

1  cir.  =360°  =  21,600' =  1,296,000". 

AVOIRDUPOIS  WEIGHT 

437.5  grains  (gr.),    ....    =1  ounce  (oz.) 

16      ounces, =1  pound  (Ib.) 

100      pounds, =1  hundredweight  (cwt.) 

20      cwt.  or  2,000  Ib.,   .    .    =1  ton  (T.) 
1  T.  =20  cwt.  =  2,000  Ib.  =32,000  oz.  =  14,000,000  gr. 
The  avoirdupois  pound  contains  7,000  grains. 

DRY  MEASURE  , 

2      pints  (pt.), =1  quart  (qt.) 

8      quarts, =1  peck  (pk.) 

4  pecks, =  1  bushel  (bu.) 

1  bu.=4  pk.  =  32  qt.  =  64  pt. 

The  U.  S.  struck  bushel  contains  2,150.42  cubic  inches  = 
1.2444  cubic  feet.  By  law,  its  dimensions  are  those  of  a 
cylinder  18V2  inches  in  diameter  and  8  inches  deep.  The 


ELECTRIC  INTERLOCKING   HANDBOOK 


389 


heaped  bushel  is  equal  to  11A  struck  bushels,  the  cone  being 
six  inches  high.  The  dry  gallon  contains  268.8  cubic  inches, 
being  %  of  a  struck  bushel. 

For  approximations,  the  bushel  may  be  taken  at  1}4  cubic 
feet,  or  a  cubic  foot  may  be  considered  %  of  a  bushel. 

The  British  bushel  contains  2,218.19  cubic  inches -1.2837 
cubic  feet  =  1.032  U.  S.  bushels. 

LIQUID  MEASURE 

4      gills  (gi.), =  lpint(pt.) 

2      pints, =1  quart  (qt.) 

4      quarts, =1  gallon  (gal.) 

3iy2  gallons,    ......    =1  barrel  (bbl.) 

2      barrels, =  1  hogshead  (hhd.) 

1  hhd.  =2  bbl.  =  63  gal.  =252  qt.  =  504  pt.  =  2,016  gi. 

The  U.  S.  gallon  contains  231  cubic  inches  =  .134  cubic  feet 
approximate ;  or  1  cubic  foot  contains  7.481  gallons.  The  fol- 
lowing cylinders  contain  the  given  measures  very  closely : 


Diam.  Height 

Gill, 1%  in.       3  in. 

Pint, 3V2  in.       3  in. 

Quart, ....  3J/2  in.       6  in. 


Gallon, . 

8  gallons, 

10  gallons, 


Diam.  Height 

7  in.  6  in. 

14  in.  12  in. 

14  in.  15  in. 


foot 


When    water   is   at    its   maximum    density,  1    cubic 
weighs  62.425  pounds  and  1  gallon  weighs  8.345  pounds. 

For  approximations,  1  cubic  foot  of  water  is  considered 
equal  to  1V-2  gallons  and  1  gallon  as  weighing  8Vs  pounds. 

The  British  Imperial  gallon,  both  liquid  and  dry,  contains 
277.274  cubic  inches  =.16046  cubic  feet,  and  is  equivalent  to 
the  volume  of  10  pounds  of  pure  water  at  62  degrees  Fahr. 
To  reduce  British  to  U.  S.  liquid  gallons,  multiply  by  1.2.  Con- 
versely, to  convert  U.  S.  into  British  liquid  gallons,  divide 
by  1.2;  or,  increase  the  number  of  gallons  3/5. 

MISCELLANEOUS  TABLE 

12  articles, =1  dozen. 

12  dozen, ==1  gross. 

12  gross, =  1  great  gross. 

2  articles, =1  pair. 

20  articles, =1  score. 

24  sheets, =1  quire. 

20  quires, =1  ream. 


390  GENERAL  RAILWAY  SIGNAL  COMPANY 


FRENCH  OR  METRIC  MEASURE 

The  metric  unit  of  length  is  the  metre  =  39. 37  inches. 

The  metric  unit  of  weight  is  the  gram  =  15.432  grains. 

The  following  prefixes  are  used  for  subdivisions  and  multi- 
ples: Milli  =  1/1000,  Centi  =  1/100,  Deci  =  l/10,  Deca  =  10, 
Hecto  =  100,  Kilo  =  1000,  Myria  =  10,000. 


FRENCH   EQUIVALENTS   OF  AMERICAN  AND 
BRITISH   MEASURE 

MEASURES  OP  LENGTH 

French  British  and  U.  S. 

(39.37  inches 

1  metre, =  '   or  3.28083  feet 

(  or  1.09361  yards 

.3048  metre, =1  foot 

1  centimetre, =  .3937  inch 

2.54  centimetres, =1  inch 

1  millimetre, 

25.4  millimetres, =1  inch 


1  kilometre, =  j  1093..  61  yard 


0.62137  mile 


MEASURES  OF  SURFACE 
French  British  and  U.  S, 

(  10.764  square  feet 
1  square  metre, -=  -j    1496  square  yard 

.836  square  metre, =1  square  yard 

.0929  square  metre, =1  square  foot 

1  square  centimetre, =.155  square  inch 

2  square  centimetres,    .    .    .    .  =  1  square  inch 


6.452  square  centimetres 
1  square  millimetre, 


f  .00155  square  inch 
\  1973.5  circular  mils. 
645.2  square  millimetres,     .    .    .    .    =  1  square  inch 

1  centiare  =  l  square  metre,.    .    =10.764  square  feet 
1  are  =  1  square  decametre, .    .    =1076.41  square  feet 

1AA  (  107641  square  feet 

1  hectare  =  100  ares, ==  j  2.4711  acres 

,  .,  /  .386109  square  mile 

1  square  kilometre, m  <  247  11  acres 

1  square  myriametre,   ....    =38.6109  square  miles 

Reprinted  by  permission  from  "  Kent's  Mechanical  Engineer's  Pocket  Book." 


ELECTRIC  INTERLOCKING  HANDBOOK  391 

MEASURES  OF  VOLUME 
French  British  and  U.  S. 

{  35.314  cubic  feet 
1  cubic  metre, =  ]  1.308  cubic  yards 

.7645  cubic  metre, =1  cubic  yard 

.02832  cubic  metre, =1  cubic  foot 

1  cubic  decimetre, : 


28.32  cubic  decimetres,    .....  =1  cubic  foot 

1  cubic  centimetre,    .....  =.061  cubic  inch 

16.387  cubic  centimetres,  .....  =1  cubic  inch 

1  cubic  centimetre  =  1  millilitre,  =  .061  cubic  inch 

1  centilitre,  .........  =  .610  cubic  inch 

1  decilitre,  .........  =6.102  cubic  inches 

1  litres  cubic  decimetre,  .  -  | 


1  hectolitre  or  decistere,  .    .    .    =        m  .  S 

1  stere,  kilolitre,  or  cubic  metre,  -  { 

MEASURES  OF  CAPACITY 
French  British  and  U.  S. 

(61.023  cubic  inches 
.03531  cubic  foot 
.2642  gallon  (Am.) 
2.202  pounds  of 
water  at  62°  Fahr. 
28.317  litres,    ..........    =1  cubic  foot 

4.543  litres,    ..........    =1  gallon  (British) 

3.785  litres,    ..........    =1  gallon  (American) 

MEASURES  OF  WEIGHT 

French  British  and  U.  S. 

1  gramme,  .........    =  15.432  grains 

.0648  gramme,  .........    =1  grain  . 

28.35  grammes,  .........    =  1  ounce  avoirdupois 

1  kilogramme,     .......    =2.2046  pounds 

.4536  kilogramme  ........    =1  pound 

f.9842    ton    of    2,240 

1  tonne  or  metric  ton,  pounds 

1,000  kilogrammes,  .......    =1  19.68  cwts. 

i.  2204.6  pounds 

1.016  metric  tons,  =  [1  ton  of  2,240 

1,016  kilogrammes,  .......     =  [pounds 


Reprinted  by  permission  from,  "Kent's  Mechanical  Engineers'  Pocket  Book." 


392 


GENERAL  RAILWAY  SIGNAL  COMPANY 


TEMPERATURES,  FAHRENHEIT   AND   CENTIGRADE 


F. 

C. 

F. 

C. 

F. 

C. 

F. 

C. 

F. 

C.  ||  F. 

C.   F. 

C. 

-40 

—40. 

26 

—3.3 

92 

33.3 

158 

70. 

224 

106.7 

290 

143.3 

360 

182.2 

—39 

—39.4 

27 

—2.8 

93 

33.9 

159 

70.6 

225 

107.2 

291 

143.9 

370 

187.8 

-38 

-38.9 

28 

—2.2 

94 

34.4 

160 

71.1 

226 

107.8 

292 

144.4 

380 

193.3 

—37 

—38.3 

29 

-1.7 

95 

35. 

161 

71.7 

227 

108.3 

293 

145. 

390 

198.9 

-36 

—37.8 

30 

—1.1 

96 

35.6 

162 

72.2 

228 

108.9 

294 

145.6 

400 

204.4 

—35 

-37.2 

31 

-0.6 

97 

36.1 

163 

72.8 

229 

109.4 

295 

146.1 

410 

210. 

34 

-36.7 

32 

0. 

98 

36.7 

164 

73.3 

230 

110. 

296 

146.7 

420 

215.6 

—33 

-36.1 

33 

+0.6 

99 

37.2 

165 

73.9 

231 

110.6 

297 

147.2 

430 

221.1 

-32 

—35.6 

34 

1.1 

100 

37.8 

166 

74.4 

232 

111.1 

298 

147.8 

440 

226.7 

—31 

-35. 

35 

1.7 

101 

38.3 

167 

75. 

233 

111.7 

299 

148.3 

450 

232.2 

-30 

—34.4 

36 

2.2 

102 

38.9 

168 

75.6 

234 

112.2 

300 

148.9 

460 

237.8 

-29 

-33.9 

37 

2.8 

103 

39.4 

169 

76.1 

235 

112.8 

301 

149.4 

470 

243.3 

—28 

—33.3 

38 

3.3 

104 

40. 

170 

76.7 

236 

113.3 

302 

150. 

480 

248.9 

—27 

-32.8 

39 

3.9 

105 

40.6 

171 

77.2 

237 

113.9 

303 

150.6 

490 

254.4 

—26 

—32.2 

40 

4.4 

106 

41.1 

172 

77.8 

238 

114.4 

304 

151.1 

500 

260. 

-25 

-31.7 

41 

5. 

107 

41.7 

173 

78.3 

239 

115. 

305 

151.7 

510 

265.6 

—24 

—31.1 

42 

5.6 

108 

42.2 

174 

78.9 

240 

115.6 

306 

152.2 

520 

271.1 

-23 

-30.6 

43 

6.1 

109 

42.8 

175 

79.4 

241 

116.1 

307 

152.8 

530 

276.7 

—22 

-30. 

44 

6.7 

110 

43.3 

176 

80. 

242 

116.7 

308 

153.3 

540 

282.2 

-21 

—29.4 

45 

7.2 

111 

43.9 

177 

80.6 

243 

117.2 

309 

153.9 

550 

287.8 

—20 

-28.9 

46 

7.8 

112 

44.4 

178 

81.1 

244 

117.8 

310 

154.4 

560 

293.3 

-19 

-28.3 

47 

8.3 

113 

45. 

179 

81.7 

245 

118.3 

311 

155. 

570 

298.9 

—18 

—27.8 

48 

8.9 

114 

45.6 

180 

82.2 

246 

118.9 

312 

155.6 

580 

304.4 

—17 

-27.2 

49 

9.4 

115 

46.1 

181 

82.8 

247 

119.4 

313 

156.1 

590 

310. 

—16 

-26.7 

50 

10. 

116 

46.7 

182 

83.3 

248 

120. 

314 

156.7 

600 

315.6 

—15 

—26.1 

51 

10.6 

117 

47.2 

183 

83.9 

249 

120.6 

315 

157.2 

610 

321.1 

—14 

—25.6 

52 

11.1 

118 

47.8 

184 

84.4 

250 

121.1 

316 

157.8 

620 

326.7 

-13 

-25. 

53 

11.7 

119 

48.3 

185 

85. 

251 

121.7 

317 

158.3 

630  332.2 

—12 

—24.4 

54 

12.2 

120 

48.9 

186 

85.6 

252 

122.2 

318 

158.9 

640  337.8 

—11 

-23.9 

55 

12.8 

121 

49.4 

187 

86.1 

253 

122.8 

319 

159.4 

650  343.3 

—10 

-23.3 

56 

13.3 

122 

50. 

188 

86.7 

254 

123.3 

320 

160. 

660  348.9 

—  9 

—22.8 

57 

13.9 

123 

50.6 

189 

87.2 

255 

123.9 

321 

160.6 

670  354.4 

—  8 

-22.2 

58 

14.4 

124 

51.1 

190 

87.8 

256 

124.4 

322 

161.1 

680  360. 

—  7 

—21.7 

59 

15. 

125 

51.7 

191 

88.3 

257 

125. 

323 

161.7 

690  J365.6 

—  6 

—21.1 

60 

15.6 

126 

52.2 

192 

88.9 

258 

125.6 

324 

162.2 

700  371.1 

—  5 

—20.6 

61 

16.1 

127 

52.8 

193 

89.4 

259 

126.1 

325 

162.8 

710  |376.7 

—  4 

-20. 

62 

16.7 

128 

53.3 

194 

90. 

260 

126.7 

326 

163.3 

720 

382.2 

—  3 

—19.4 

63 

17.2 

129 

53.9 

195 

90.6 

261 

127.2 

327 

163.9 

730 

387.8 

2 

-18.9 

64 

17.8 

130 

54.4 

196 

91.1 

262 

127.8 

328 

164.4 

740 

393.3 

* 

—18.3 

65 

18.3 

131 

55. 

197 

91.7 

263 

128.3 

329 

165. 

750 

398.9 

0 

—17.8 

66 

18.9 

132 

55.6 

198 

92.2 

264 

128.9 

330 

165.6 

760 

404.4 

+  1 

—17.2 

67 

19.4 

133 

56.1 

199 

92.8 

265 

129.4 

331 

166.1 

770 

410. 

2 

—16.7 

68 

20. 

134 

56.7 

200 

93.3 

266 

130. 

332 

166.7 

780 

415.6 

3 

—16.1 

69 

20.6 

135 

57.2 

201 

93.9 

267 

130.6 

333 

167.2 

790 

421.1 

4 

—15.6 

70 

21.1 

136 

57.8 

202 

94.4 

268 

131.1 

334 

167.8 

800 

426.7 

5 

—15. 

71 

21.7 

137 

58.3 

203 

95. 

269 

131.7 

335 

168.3 

810 

432.2 

6 

—14.4 

72 

22.2 

138 

58.9 

204 

95.6 

270 

132.2 

336 

168.9 

820 

437.8 

7 

-13.9 

73 

22.8 

139 

59.4 

205 

96.1 

271 

132.8 

337 

169.4 

830 

443.3 

8 

—13.3 

74 

23.3 

140 

60. 

206 

96.7 

272 

133.3 

338 

170. 

840 

448.9 

9 

-12.8 

75 

23.9 

141 

60.6 

207 

97.2 

273 

133.9 

339 

170.6 

850 

454.4 

10 

—12.2 

76 

24.4 

142 

61.1 

208 

97.8 

274 

134.4 

340 

171.1 

860 

460. 

11 

—11.7 

77 

25. 

143 

61.7 

209 

98.3 

275 

135. 

341 

171.7 

870 

465.6 

12 

—11.1 

78 

25.6 

144 

62.2 

210 

98.9 

276 

135.6 

342 

172.2 

880 

471.1 

13 

—10.6 

79 

26.1 

145 

62.8 

211 

99.4 

277 

136.1 

343 

172.8 

890 

476.7 

14 

—10. 

80 

26.7 

146 

63.3 

212 

100. 

278 

136.7 

344 

173.3 

900 

482.2 

15 

—  9.4 

81 

27.2 

147 

63.9 

213 

100.6 

279 

137.2 

345 

173.9 

910 

487.8 

16 

—  8.9 

82 

27.8 

148 

64.4 

214 

101.1 

280 

137.8 

346 

174.4 

920 

493.3 

17 

—  8.3 

83 

28.3 

149 

65. 

215 

101.7 

281 

138.3 

347 

175. 

930 

498.9 

18 

—  7.8 

84 

28.9 

150 

65.6 

216 

102.2 

282 

138.9 

348 

175.6 

940 

504.4 

19 

-  7.2 

85 

29.4 

151 

66.1 

217 

102.8 

283 

139.4 

349 

176.1 

950 

510. 

20 

—  6.7 

86 

30. 

152 

66.7 

218 

103.3 

284 

140. 

350 

176.7 

960 

515.6 

21 

—  6.1 

87 

30.6 

153 

67.2 

219 

103.9 

285 

140.6 

351 

177.2 

970 

521.1 

22 

—  5.6 

88 

31.1 

154 

67.8 

220 

104.4 

286 

141.1 

352 

177.8 

980 

526.7 

23 

—  5. 

89 

31.7 

155 

68.3 

221 

105. 

287 

141.7 

353 

178.3 

990 

532.2 

24 

—  4.4 

90 

32.2 

156 

68.9 

222 

105.6 

288 

142.2 

354 

178.9 

1000 

537.8 

25 

—  3.9 

91 

32.8 

157 

69.4 

223 

106.1 

289 

142.8 

355 

179.41010 

543  3 

Reprinted  by  -permission  from  "Kent's  Mechanical  Engineers'  Pocket  Book." 


ELECTRIC   INTERLOCKING   HANDBOOK 


393 


TEMPERATURES,  CENTIGRADE  AND  FAHRENHEIT 


c. 

F. 

C. 

F. 

C. 

F. 

C. 

F. 

C. 

F. 

C. 

F. 

C. 

F. 

—40 

-40. 

26 

78.8 

92 

197.6 

158 

316.4 

224 

435.2 

290 

554 

950 

1742 

—39 

—38.2 

27 

80.6 

93 

199.4 

159 

318.2 

225 

437. 

300 

572 

960 

1760 

—38 

—36.4 

28 

82.4 

94 

201.2 

160 

320. 

226 

438.8 

310 

590 

970 

1778 

—37 

—34.6 

29 

84.2 

95 

203. 

161 

321.8 

227 

440.6 

320 

608 

980 

1796 

-36 

-32.8 

30 

86. 

96 

204.8 

162 

323.6 

228 

442.4 

330 

626 

990 

1814 

-35 

-31. 

31 

87.8 

97 

206.6 

163 

325.4 

229 

444.2 

340 

644 

1000 

1832 

—34 

—29.2 

32 

89.6 

98 

208.4 

164 

327.2 

230 

446. 

350 

662 

1010 

1850 

-33 

-27.4 

33 

91.4 

99 

210.2 

165 

329. 

231 

447.8 

360 

680 

1020 

1868 

—32 

-25.6 

34 

93.2 

100 

212. 

166 

330.8 

232 

449.6 

370 

698 

1030 

1886 

-31 

—23.8 

35 

95. 

101 

213.8 

167 

332.6 

233 

451.4 

380 

716 

1040 

1904 

—30 

—22. 

36 

96.8 

102 

215.6 

168 

334.4 

234 

453.2 

390 

734 

1050 

1922 

—29 

—20.2 

37 

98.6 

103 

217.4 

169 

336.2 

235 

455. 

400 

752 

1060 

1940 

-28 

-18.4 

38 

100.4 

104 

219.2 

170 

338. 

236 

456.8 

410 

770 

1070 

1958 

—27 

—16.6 

39 

102.2 

105 

221. 

171 

339.8 

237 

458.6 

420 

788 

1080 

1976 

—26 

—14.8 

40 

104. 

106 

222.8 

172 

341.6 

238 

460.4 

430 

806 

1090 

1994 

—25 

-13. 

41 

105.8 

107 

224.6 

173 

343.4 

239 

462.2 

440 

824 

1100 

2012 

24 

-11.2 

42 

107.6 

108 

226.4 

174 

345.2 

240 

464. 

450 

842 

1110 

2030 

—23 

—  9.4 

43 

109.4 

109 

228.2 

175 

347. 

241 

465.8 

460 

860 

1120 

2048 

—22 

—  7.6 

44 

111.2 

110 

230. 

176 

348.8 

242 

467.6 

470 

878 

1130 

2066 

—21 

-5.8 

45 

113. 

111 

231.8 

177 

350.6 

243 

469.4 

480 

896 

1140 

2084 

-20 

—  4. 

46 

114.8 

112 

233.6 

178 

352.4 

244 

471.2 

490 

914 

1150 

2102 

—19 

—  2.2 

47 

116.6 

113 

235.4 

179 

354.2 

245 

473. 

500 

932 

1160 

2120 

—18 

—  0.4 

48 

118.4 

114 

237.2 

180 

356. 

246 

474.8 

510 

950 

1170 

2138 

-17 

+  1.4 

49 

120.2 

115 

239. 

181 

357.8 

247 

476.6 

520 

968 

1180 

2156 

—16 

3.2 

50 

122. 

116 

240.8 

182 

359.6 

248 

478.4 

530 

986 

1190 

2174 

—15 

5. 

51 

123.8 

117 

242.6 

183 

361.4 

249 

480.2 

540 

1004 

1200 

2192 

-14 

6.8 

52 

125.6 

118 

244.4 

184 

363.2 

250 

482. 

550 

1022 

1210 

2210 

—13 

8.6 

53 

127.4 

119 

246.2 

185 

365. 

251 

483.8 

560 

1040 

1220 

2228 

—12 

10.4 

54 

129.2 

120 

248. 

186 

366.8 

252 

485.6 

570 

1058 

1230 

2246 

—11 

12.2 

55 

131. 

121 

249.8 

187 

368.6 

253 

487.4 

580 

1076 

1240 

2264 

—10 

14. 

56 

132.8 

122 

251.6 

188 

370.4 

254 

489.2 

590 

1094 

1250 

2282 

—  9 

15.8 

57 

134.6 

123 

253.4 

189 

372.2 

255 

491. 

600 

1112 

1260 

2300 

—  8 

17.6 

58 

136.4 

124 

255.2 

190 

374. 

256 

492.8 

610 

1130 

1270 

2318 

—  7 

19.4 

59 

138.2 

125 

257. 

191 

375.8 

257 

494.6 

620 

1148 

1280 

2336 

—  6 

21.2 

60 

140. 

126 

258.8 

192 

377.6 

258 

496.4 

630 

1166 

1290 

2354 

—  5 

23. 

61 

141.8 

127 

260.6 

193 

379.4 

259 

498.2 

640 

1184 

1300 

2372 

A 

24.8 

62 

143.6 

128 

262.4 

194 

381.2 

260 

500. 

650 

1202 

1310 

2390 

—  3 

26.6 

63 

145.4 

129 

264.2 

195 

383. 

261 

501.8 

660 

1220 

1320 

2408 

—  2 

28.4 

64 

147.2 

130 

266. 

196 

384.8 

262 

.503.6 

670 

1238 

1330 

2426 

—  1 

30.2 

65 

149. 

131 

267.8 

197 

386.6 

263 

505.4 

680 

1256 

1340 

2444 

0 

32. 

66 

150.8 

132 

269.6 

198 

388.4 

264 

507.2 

690 

1274 

1350 

2462 

+  1 

33.8 

67 

152.6 

133 

271.4 

199 

390.2 

265 

509. 

700 

1292 

13GO 

2480 

2 

35.6 

68 

154.4 

134 

273.2 

200 

392. 

266 

510.8 

710 

1310 

1370 

2498 

3 

37.4 

69 

156.2 

135 

275. 

201 

393.8 

267 

512.6 

720 

1328 

1380 

2516 

4 

39.2 

70 

158. 

136 

276.8 

202 

395.6 

268 

514.4 

730 

1346 

1390 

2534 

5 

41. 

71 

159.8 

137 

278.6 

203 

397.4 

269 

516.2 

740 

1364 

1400 

2552 

6 

42.8 

72 

161.6 

138 

280.4 

204 

399.2 

270 

518. 

750 

1382 

1410 

2570 

7 

44.6 

73 

163.4 

139 

282.2 

205 

401. 

271 

519.8 

760 

1400 

1420 

2588 

8 

46.4 

74 

165.2 

140 

284. 

206 

402.8 

272 

521.6 

770 

1418 

1430 

2606 

9 

48.2 

75 

167. 

141 

285.8 

207 

404.6 

273 

523.4 

780 

1436 

1440 

2624 

10 

50. 

76 

168.8 

142 

287.6 

208 

406.4 

274 

525.2 

790 

1454 

1450 

2642 

11 

51.8 

77 

170.6 

143 

289.4 

209 

408.2 

275 

527. 

800 

1472 

1460 

2660 

12 

53.6 

78 

172  .4 

144 

291.2 

210 

410. 

276 

528.8 

810 

1490 

1470 

2678 

13 

55.4 

79 

174.2 

145 

293. 

211 

411.8 

277 

530.6 

820 

1508 

1480 

2696 

14 

57.2 

80 

176. 

146 

294.8 

212 

413.6 

278 

532.4 

830 

1526 

1490 

2714 

15 

59. 

81 

177.8 

147 

296.6 

213 

415.4 

279 

534.2 

840 

1544 

1500 

2732 

16 

60.8 

82 

179.6 

148 

298.4 

214 

417.2 

280 

536. 

850 

1562 

1510 

2750 

17 

62.6 

83 

181.4 

149 

300.2 

215 

419. 

281 

537.8 

860 

1580 

1520 

2768 

18 

64.4 

84 

183.2 

150 

302. 

216 

420.8 

282 

539.6 

870 

1598 

1530 

2786 

19 

66.2 

85 

185. 

151 

303.8 

217 

422.6 

283 

541.4 

880 

1616 

1540 

2804 

20 

68. 

86 

186.8 

152 

305.6 

218 

424.4 

284 

543.2 

890 

1634 

1550 

2822 

21 

69.8 

87 

188.6 

153 

307.4 

219 

426.2 

285 

545. 

900 

1652 

1600 

2912 

22 

71.6 

88 

190.4 

154 

309.2 

220 

428. 

286 

546.8 

910 

1670 

1650 

3002 

23 

73.4 

89 

192.2 

155 

311. 

221 

429.8 

287 

548.6 

920 

1688 

1700 

3092 

24 

75.2 

90 

194. 

156 

312.8 

222 

431.6 

288,  550.4 

930 

1706 

1750 

3182 

25  77.  |l  91 

195.8  157 

314.6 

223 

433.4  289!  552.2 

940 

1724 

1800 

3272 

Reprinted  by  permission  from  "Kent's  Mechanical  Engineers'  Pocket  Book.' 


394 


GENERAL  RAILWAY  SIGNAL  COMPANY 


SQUARES,  CUBES,  SQUARE   ROOTS  AND   CUBE   ROOTS  OF 
NUMBERS   FROM   0.1    TO    100 


No. 

Square 

Cube 

Sq. 
Root 

Cube 
Root 

No. 

Square 

Cube 

Sq. 
Root 

Cube 
Root 

0.1 

.01 

.001 

.3162 

.4642 

3.1 

9.61 

29.791 

.761 

.-458 

.15 

.0225 

.0034 

.3873 

.5313 

.2 

10.24 

32.768 

.789 

.474 

.2 

.04 

.008 

.4472 

.5848 

.3 

10.89 

35.937 

.817 

.489 

.25 

.0625 

.0158 

.500 

.6300 

.4 

11.56 

39.304 

.844 

.504 

.3 

.09 

.027 

.5477 

.6694 

.5 

12.25 

42.875 

.871 

.518 

.35 

.1225 

.0429 

.5916 

.7047 

.6 

12.96 

46.656 

.897 

.533 

.4 

.16 

.064 

.6325 

.7368 

.7 

13.69 

50.653 

.924 

.547 

.45 

.2025 

.0911 

.6708 

.7663 

.8 

14.44 

54.872 

.949 

.560 

.5 

.25 

.125 

.7071 

.7937 

.9 

15.21 

59.319 

1.975 

.574 

.55 

.3025 

.1664 

.7416 

.8193 

4. 

16. 

64. 

2. 

.5874 

.6 

.36 

.216 

.7746 

.8434 

.1 

16.81 

68.921 

2.025 

.601 

.65 

.4225 

.2746 

.8062 

.8662 

.2 

17.64 

74.088 

2.049 

.613 

.7 

.49 

.343 

.8367 

.8879 

.3 

18.49 

79.507 

2.074 

.626 

.75 

.5625 

.4219 

.8660 

.9086 

.4 

19.36 

85.184 

2.098 

.639 

.8 

.64 

.512 

.8944 

.9283 

.5 

20.25 

91.125 

2.121 

.651 

.85 

.7225 

.6141 

.9219 

.9473 

.6 

21.16 

97.336 

2.145 

.663 

.9 

.81 

.729 

.9487 

.9655 

.7 

22.09 

103.823 

2.168 

.675 

.95 

.9025 

.8574 

.9747 

.9830 

.8 

23.04 

110.592 

2.191 

.687 

t 

1. 

1. 

.9 

24.01 

117.649 

2.214 

.698 

.05 

1.1025 

'.158 

'.025 

1.016 

5. 

25. 

125. 

2.2361 

.7100 

.1 

1.21 

.331 

.049 

1.032 

.1 

26.01 

132.651 

2.258 

1.721 

.15 

1.3225 

.521 

.072 

1.048 

.2 

27.04 

140.608 

2.280 

1.732 

.2 

.44 

.728 

.095 

1.063 

.3 

28.09 

148.877 

2.302 

1.744 

.25 

.5625 

.953 

.118 

1.077 

.4 

29.16 

157.464 

2.324 

1.754 

.3 

.69 

2.197 

.140 

1.091 

.5 

30.25 

166.375 

2.345 

1.765 

1.35 

.8225 

2.460 

1.162 

1.105 

.6 

31.36 

175.616 

2.366 

1.776 

1.4 

:  .96 

2.744 

1.183 

.119 

.7 

32.49 

185.193 

2.387 

1.786 

1.45 

2.1025 

3.049 

1.204 

.132 

.8 

33.64 

195.112 

2.408 

1.797 

1.5 

2.25 

3.375 

.2247 

.1447 

.9 

34.81 

205.379 

2.429 

1.807 

1.55 

2.4025 

3.724 

.245 

.157 

6. 

36. 

216. 

2.4495 

1.8171 

1.6 

2.56 

4.096 

.265 

.170 

.1 

37.21 

226.981 

2.470 

.827 

1.65 

2.7225 

4.492 

.285 

.182 

.2 

38.44 

238.328 

2.490 

.837 

1.7 

2.89 

4.913 

.304 

.193 

.3 

39.69 

250.047 

2.510 

.847 

1.75 

3.0625 

5.359 

.323 

.205 

.4 

40.96 

262.144 

2.530 

.857 

1.8 

3.24 

5.832 

.342 

.216 

.5 

42.25 

274.625 

2.550 

.866 

1.85 

3.4225 

6.332 

.360 

.228 

.6 

43.56 

287.496 

2.569 

.876 

1.9 

3.61 

6.859 

.378 

.239 

.7 

44.89 

300.763 

2.588 

.885 

1.95 

3.8025 

7.415 

.396 

.249 

.8 

46.24 

314.432 

2.608 

.895 

2. 

4. 

8. 

.4142 

.2599 

.9 

47.61 

328.509 

2.627 

.904 

.1 

4.41 

9.261 

.449 

1.281 

7. 

49. 

343. 

2.6458 

.9129 

.2 

4.84 

10.648 

1.483 

1.301 

.1 

50.41 

357.911 

2.665 

.922 

.3 

5.29 

12.167 

1.517 

1.320 

.2 

51.84 

373.248 

2.683 

.931 

.4 

5.76 

13.824 

1.549 

1.389 

.3 

53.29 

389.017 

2.702 

.940 

.5 

6.25 

15.625 

1.581 

1.357 

.4 

54.76 

405.224 

2.720 

.949 

.6 

6.76 

17.576 

1.612 

1.375 

.5 

56.25 

421.875 

2.739 

.957 

.7 

7.29 

19.683 

1.643 

1.392 

.6 

57.76 

438.976 

2.757 

1.966 

.8 

7.84 

21.952 

1.673 

1.409 

.7 

59.29 

456.533 

2.775 

1.975 

.9 

8.41 

24.389 

1.703 

1.426 

.8 

60.84 

474.552 

2.793 

1.983 

3. 

9. 

27. 

1.7321 

1.4422 

.9 

62.41 

493.039 

2.811 

1.992 

Reprinted  by  permission  from  "Kent's  Mechanical  Engineers'  Pocket  Book." 


ELECTRIC  INTERLOCKING  HANDBOOK 


395 


No. 

Square 

Cube 

Sq. 
Root 

Cube 
Root 

No. 

Sq. 

Cube 

Sq. 
Root 

Cube 
Root 

8. 

64. 

512. 

2.8284 

2. 

45 

2025 

91125 

6.7082 

3.5569 

.1 

65.61 

531.441 

2.846 

2.008 

46 

2116 

97336 

6.7823 

3.5830 

.2 

67.24 

551.368 

2.864 

2.017 

47 

2209 

103823 

6.8557 

3.6088 

.3 

68.89 

571.787 

2.881 

2.025 

48 

2304 

110592 

6.9282 

3.6342 

A 

70.56 

592.704 

2.898 

2.033 

49 

2401 

117649 

7. 

3.6593 

.5 

72.25 

614.125 

2.915 

2.041 

50 

2500 

125000 

7.0711 

3.6840 

.6 

73.96 

636.056 

2.933 

2.049 

51 

2601 

132651 

7.1414 

3.7084 

.7 

75.69 

658.503 

2.950 

2.057 

52 

2704 

140608 

7.2111 

3.7325 

.8 

77.44 

681.472 

2.966 

2.065 

53 

2809 

148877 

7.2801 

3.7563 

.9 

79.21 

704.969 

2.983 

2.072 

54 

2916 

157464 

7.3485 

3.7798 

9. 

81. 

729. 

3. 

2.0801 

55 

3025 

166375 

7.4162 

3.8030 

.1 

82.81 

753.571 

3.017 

2.088 

56 

3136 

175616 

7.4833 

3.8259 

.2 

84.64 

778.688 

3.033 

2.095 

57 

3249 

185193 

7.5498 

3.8485 

.3 

86.49 

804.357 

3.050 

2.103 

58 

3364 

195112 

7.6158 

3.8709 

.4 

88.36 

830.584 

3.066 

2.110 

59 

3481 

205379 

7.6811 

3.8930 

.5 

90.25 

857.375 

3.082 

2.118 

60 

3600 

216000 

7.7460 

3.9149 

.6 

92.16 

884.736 

3.098 

2.125 

61 

3721 

22G981 

7.8102 

3.9365 

.7 

94.09 

912.673 

3.114 

2.133 

62 

3844 

238328 

7.8740 

3.9579 

.8 

96.04 

941.192 

3.130 

2.140 

63. 

3969 

250047 

7.9373 

3.9791 

.9 

98.01 

970.299 

3.146 

2.147 

64 

4096 

262144 

8. 

4. 

10 

100 

1000 

3.1623 

2.1544 

65 

4225 

274625 

8.0623 

4.0207 

11 

121 

1331 

3.3166 

2.2240 

66 

4356 

287496 

8.1240 

4.0412 

12 

144 

1728 

3.4641 

2.2894 

67 

4489 

300763 

8.1854 

4.0615 

13 

169 

2197 

3.6056 

2.3513 

68 

4624 

314432 

8.2462 

4.0817 

14 

196 

2744 

3.7417 

2.4101 

69 

4761 

328509 

8.3066 

4.1016 

15 

225 

3375 

3.8730 

2.4662 

70 

4900 

343000 

8.3666 

4.1213 

16 

256 

4096 

4. 

2.5198 

71 

5041 

357911 

8.4261 

4.1408 

17 

289 

4913 

4.1231 

2.5713 

72 

5184 

373248 

8.4853 

4.1602 

18 

324 

5832 

4.2426 

2.6207 

73 

5329 

389017 

8.5440 

4.1793 

19 

361 

6859 

4.3589 

2.6684 

74 

5476 

405224 

8.6023 

4.1983 

20 

400 

8000 

4.4721 

2.7144 

75 

5625 

421875 

8.6603 

4.2172 

21 

441 

9261 

4.5826 

2.7589 

76 

5776 

438976 

8.7178 

4.2358 

22 

484 

10648 

4.6904 

2.8020 

77 

5929 

456533 

8.7750 

4.2543 

23 

529 

12167 

4.7958 

2.8439 

78 

6084 

474552 

8.8318 

4.2727 

24 

576 

13824 

4.8990 

2.8845 

79 

6241 

493039 

8.8882 

4.2908 

25 

625 

15625 

5. 

2.9240 

80 

6400 

512000 

8.9443 

4.3089 

26 

676 

17576 

5.0990 

2.9625 

81 

6561 

531441 

9. 

4.3267 

27 

729 

19683 

5.1962 

3. 

82 

6724 

551368 

9.0554 

4.3445 

28 

784 

21952 

5.2915 

3.0366 

83 

6889 

571787 

9.1104 

4.3621 

29 

841 

24389 

5.3852 

3.0723 

84 

7056 

592704 

9.1652 

4.3795 

30 

900 

27000 

5.4772 

3.1072 

85 

7225 

614125 

1  9.2195 

4.3968 

31 

961 

29791 

5.5678 

3.1414 

86 

7396 

636056 

9.2736 

4.4140 

32 

1024 

32768 

5.6569 

3.1748 

87 

7569 

658503 

9.3276 

4.4310 

33 

1089 

35937 

5.7446 

3.2075 

88 

7744 

681472 

9.3808 

4.4480 

34 

1156 

39304 

5.8310 

3.2396 

89 

7921 

704969 

9.4340 

4.4647 

35 

1225 

42875 

5.9161 

3.2711 

90 

8100 

729000 

9.4868 

4.4814 

36 

1296 

46656 

6. 

3.3019 

91 

8281 

753571 

9.5394 

4.4979 

37 

1369 

50653 

6.0828 

3.3322 

92 

8464 

778688 

9.5917 

4.5144 

38 

1444 

54872 

6.1644 

3.3620 

93 

8649 

804357 

9.6437 

4.5307 

39 

1521 

59319 

6.2450 

3.3912 

94 

8836 

830584 

9.6954 

4.5468 

40 

1600 

64000 

6.3246 

3.4200 

95 

9025 

857375 

9.7468 

4.5629 

41 

1681 

68921 

6.4031 

3.4482 

96 

9216 

884736 

9.7980 

4.5789 

42 

1764 

74088 

6.4807 

3.4760 

97 

9409 

912673 

9.8489 

4.5947 

43 

1849 

79507 

6.5574 

3.5034 

98 

9604 

941192 

9.8995 

4.6104 

44 

1936 

85184 

6.6332 

3.5303 

99 

9801 

970299 

9.9499 

4.6261 

Reprinted  by  permission  from  "Kent's  Mechanical  Engineers'  Pocket  Book." 


396 


GENERAL  RAILWAY  SIGNAL  COMPANY 


COMMON   FRACTIONS  AND  THEIR  EQUIVALENTS  IN   DECIMAL 
INCHES   AND   MILLIMETERS 


Fraction 

Inches 

Milli- 
meters 

Fraction 

Inches 

Milli- 
meters 

1/64 

.0156 

.397 

3%4 

.5156 

13.10 

V32 

.0313 

.79 

17/32 

.5313 

13.50 

%4 

.0469 

1.19 

S%4 

.5469 

13.89 

*4«     %2 

.0625 

1.59 

%e    J%a 

.5625 

14.29 

%4 

.0781 

1.98 

3%4 

.5781 

14.69 

%2 
%4 

.0938 
.1094 

2.38 

2.78 

19/32 
3%4 

.5938 
.6094 

15.09 
15.48 

%  y32 

.1250 

3.18 

%   2%2 

.6250 

15.88 

%4 

.1406 

3.57 

4V64 

.6406 

16.28 

%2 

.1563 

3^97 

21/32 

.6563 

16.67 

^e* 

.1719 

4.37 

4%4 

.6719 

17.07 

%6     %2 

.1875 

4.76 

!%e   22/32 

.6875 

17.47 

13/64 

.2031 

5.16 

45/64 

.7031 

17.86 

7/32 

.2188 

5.56 

2%2 

.7188 

18.26 

15/64 

.2344 

5.95 

4%4 

.7344 

18.66 

H   %2 

.2500 

6.35 

%      24/32 

.7500 

19.01 

17/64 

.2656 

6.75 

4%4 

.7656 

19.45 

%2 

.2813 

7.15 

2%2 

.7813 

19.85 

1P/64 

.2969 

7.54 

5%4 

.7969 

20.25 

5/16   10/32 

.3125 

7.94 

13A«    2%2 

.8125 

20.64 

21/64 

.3281 

8.34 

5%4 

.8281 

21.04 

1V32 

.3438 

8.73 

2%2 

.8438 

21.44 

2%4 

.3594 

9.13 

G%4 

.8594 

21.83 

%   1%2 

.3750 

9.53 

%  28/83 

.8750 

22.23 

25/64 

.3906 

9.92 

5%4 

.8906 

22.63 

13/32 

.4063 

10.32 

2%2 

.9063 

23.02 

2%4 

.4219 

10.72 

5%4 

.9219 

23.42 

Vie  i%2 

.4375 

11.12 

15/ie  3%2 

.9375 

23.82 

2%4 

.4531 

*•    11.51 

61/64 

.9531 

24.22 

*%2 

.4688 

11.91 

3V32 

.9688 

24.61 

3V'e4 

.4844 

12.31 

6%4 

.9844 

25.01 

%     16/32 

.5000 

12.70 

1       8%2 

1  .  0000 

25  .41 

ELECTRIC  INTERLOCKING   HANDBOOK 


397 


CIRCUMFERENCE   AND    AREAS   OF   CIRCLES 


Diam. 

CIrcum. 

Area 

Diam. 

Circum. 

Area 

Diam. 

Circum. 

Area 

%4 

.04909 

.00019 

3V2 

7.8540 

4.9087 

6% 

20.813 

34.472 

$* 

.09818 

.00077 

%6 

8.0503 

5.1572 

% 

21.206 

35.785 

%4 

.14726 

.00173 

% 

8.2467 

5.4119 

% 

21.598 

37.122 

%e 

.  19635 

.00307 

*Me 

8.4430 

5.6727 

7. 

21.991 

38.485 

%2 

.29452 

.00690 

% 

8.6394 

5.9396 

Vs 

22.384 

39.871 

% 

.39270 

.01227 

13Ao 

8.8357 

6.2126 

% 

22.776 

41.282 

%2 

.49087 

.01917 

% 

9.0321 

6.4918 

% 

23.169 

42.718 

8/16 

.58905 

.02761 

15Ae 

9.2284 

6.7771 

¥2 

23.562 

44.179 

%a 

.68722 

.03758 

% 

23.955 

45.664 

3. 

9.4248 

7.0686 

% 

24.347 

47.173 

^4 

.78540 

.04909 

Me 

9.6211 

7.3662 

Vs 

24.740 

48.707 

%2 

.88357 

.06213 

Vs 

9.8175 

7.6699 

8. 

25.133 

50.265 

6/ie 

.98175 

.07670 

8Ae 

10.014 

7.9798 

% 

25.525 

51.849 

l%a 

1.0799 

.09281 

M 

10.210 

8.2958 

$ 

25.918 

53.456 

% 

1.1781 

.11045 

5Ae 

10.407 

8.6179 

% 

26.311 

55.088 

13/S2 

1.2763 

.12962 

% 

10.603 

8.9462 

¥2 

26.704 

56.745 

%e 

1.3744 

.15033 

Me 

10.799 

9.2806 

% 

27.096 

58.426 

15/S2 

1.4726 

.17257 

V2 

10.996 

9.6211 

8/4 

27.489 

60.132 

9Ae 

11.192 

9.9678 

% 

27.882 

61.862 

ft 

1.5708 

.19635 

% 

11.388 

10.321 

9. 

28.274 

63.617 

17/32 

1.6690 

.22166 

!Me 

11.585 

10.680 

Vs 

28.667 

65.397 

9/16 

1.7671 

.24850 

8/4 

11.781 

11.045 

% 

29.060 

67.201 

18/32 

1.8653 

.27688 

1%8 

11.977 

11.416 

% 

29.452 

69.029 

% 

1.9635 

.30680 

7/8 

12.174 

11.793 

V2 

29.845 

70.882 

21/32 

2.0617 

.33824 

15Ae 

12.370 

12.177 

30.238 

72.760 

!Vie 

2.1598 

.37122 

4. 

12.566 

12.566 

% 

30.631 

74.662 

2%2 

2.2580 

.40574 

Me 

12.763 

12.962 

% 

31.023 

76.589 

% 

12.959 

13.364 

10. 

31.416 

78.540 

3/4 

2.3562 

.44179 

8/16 

13.155 

13.772 

% 

31.809 

80.516 

35/32 

2.4544 

.47937 

M 

13.352 

14.186 

J/4 

32.201 

82.516 

18Ae 

2.5525 

.51849 

5Ae 

13.548 

14.607 

% 

32.594 

84.541 

27/82 

2.6507 

.55914 

% 

13.744 

15.033 

% 

32.987 

86.590 

% 

2.7489 

.60132 

7Ae 

13.941 

15.466 

% 

33.379 

88.664 

2%2 

2.8471 

.64504 

V2 

14.137 

15.904 

% 

33.772 

90.763 

15/16 

2.9452 

.69029 

8Ae 

14.334 

16.349 

7/8 

34.165 

92.886 

«V32 

3.0434 

.73708 

% 

14.530 

16.800 

11. 

34.558 

95.033 

iVie 

14.726 

17.257 

Vs 

34.950 

97.205 

1. 

3.1416 

.7854 

% 

14.923 

17.721 

M 

35.343 

99.402 

%6 

3.3379 

.8866 

18Ao 

15.119 

18.190 

% 

35.736 

101.62 

Vs 

3.5343 

.9940 

% 

15.315 

18.665 

V2 

36.128 

103.87 

8Ae 

3.7306 

1  .  1075 

15/16 

15.512 

19.147 

% 

36.521 

106.14 

% 

3.9270 

1.2272 

5. 

15.708 

19.635 

% 

36.914 

108.43 

BAe 

4.1233 

1.3530 

Me 

15.904 

20.129 

7/8 

37.306 

110.75 

% 

4.3197 

1.4849 

% 

16.101 

20.629 

12. 

37.699 

113.10 

7Ae 

4.5160 

1.6230 

8/ie 

16.297 

21.135 

Vs 

38.092 

115.47 

v2 

4.7124 

1.7671 

% 

16.493 

21.648 

w 

.38.485 

117.86 

°Ae 

4.9087 

1.9175 

6Ao 

16.690 

22.166 

% 

38.877 

120.28 

% 

5.1051 

2.0739 

% 

16.886 

22.691 

V2 

39.270 

122.72 

Wie 

5.3014 

2.2365 

7Ae 

17.082 

23.221 

39.663 

125.19 

% 

5.4978 

2.4053 

V2 

17.279 

23.758 

40.055 

127.68 

18Ae 

5.6941 

2.5802 

9Ae 

17.475 

24.301 

% 

40.448 

130.19 

7/8 

5.8905 

2.7612 

% 

17.671 

24.850 

13. 

40.841 

132.73 

15A6 

6.0868 

2.9483 

H4e 

17.868 

25.406 

Vs 

41.233 

135.30 

8/4 

18.064 

25.967 

5? 

41.626 

137.89 

2. 

6.2832 

3.1416 

18Ae 

18.261 

26.535 

% 

42.019 

140.50 

Me 

6.4795 

3.3410 

% 

18.457 

27.109 

Y2 

42.412 

143.14 

Vs 

6.6759 

3.5466 

15Ae 

18.653 

27.688 

% 

42.804 

145.80 

8Ae 

6.8722 

3.7583 

6. 

18.850 

28.274 

% 

43.197 

148.49 

% 

7.0686 

3.9761 

% 

19.242 

29.465 

% 

43.590 

LSI.  20 

BAe 

7.2649 

4.2000 

% 

19.635 

30.680 

14. 

43.982 

153.94 

% 

7.4613 

4.4301 

% 

20.028 

31.919 

Vs 

44.375 

156.70 

Me 

7.6576 

4.6664 

¥2 

20.420 

33.183 

V4 

44.768 

159.48 

Reprinted  by  permission  from  "Kent's  Mechanical  Engineers'  Pocket  Book." 


398 


GENERAL  RAILWAY  SIGNAL  COMPANY 


Diain. 

Clrcuin. 

Area 

Diarn. 

Circum. 

Area 

Diam. 

Circum. 

Area 

14«/8 

45.160 

162.30 

22y4 

69.900 

388.82 

30Vs 

94.640 

712.76 

45.553 

165.13 

% 

70.293 

393.20 

y* 

95.033 

718.69 

% 

45.946 

167.99 

Va 

70.686 

397.61 

% 

95.426 

724.64 

% 

46.338 

170.87 

71.079 

402.04 

y2 

95.819 

730.62 

% 

46.731 

173.78 

71.471 

406.49 

% 

96.211 

736.62 

15. 

47.124 

176.71 

% 

71.864 

410.97 

% 

96.604 

742.64 

47.517 

179.67 

23. 

72.257 

415.48 

% 

96.997 

748.69 

47.909 

182.65 

Vs 

72.649 

420.00 

31. 

97.389 

754.77 

48.302 

185.66 

% 

73.042 

424.56 

K 

97.782 

760.87 

48.695 

188.69 

% 

73.435 

429.13 

% 

98.175 

766.99 

49.087 

191.75 

73.827 

433.74 

% 

98.567 

773.14 

49.480 

194.83 

58 

74.220 

438.36 

V2 

98.960 

779.31 

% 

49.873 

197.93 

% 

74.613 

443.01 

% 

99.353 

785.51 

16. 

50.265 

201.06 

% 

75.006 

447.69 

% 

99.746 

791.73 

% 

50.658 

204.22 

24. 

75.398 

452.39 

% 

100.138 

797.98 

¥4 

51.051 

207.39 

Vs 

75.791 

457.11 

32. 

100.531 

804.25 

% 

51.444 

210.60 

V* 

76.184 

461.86 

tt 

100.924 

810.54 

% 

51.836 

213.82 

% 

76.576 

466.64 

y4 

101.316 

816.86 

52.229 

217.08 

Vz 

76.969 

471.44 

% 

101.709 

823.21 

52.622 

220.35 

% 

77.362 

476.26 

y2 

102.102 

829.58 

7/8 

53.014 

223.65 

% 

77.754 

481.11 

% 

102.494 

835.97 

17. 

53.407 

226.98 

% 

78.147 

485.98 

% 

102.887 

842.39 

Vs 

53.800 

230.33 

25. 

78.540 

490.87 

% 

103.280 

848.83 

$ 

54.192 

233.71 

Vs 

78.933 

495.79 

33. 

103.673 

855.30 

% 

54.585 

237.10 

¥4 

79.325 

500.74 

VH 

104.065 

861.79 

V'a 

54.978 

240.53 

% 

79.718 

505.71 

M 

104.458 

868.31 

55.371 

243.98 

¥2 

80.111 

510.71 

% 

104.851 

874.85 

|i1 

55.763 

247.45 

% 

80.503 

515.72 

y2 

105.243 

881.41 

% 

56.156 

250.95 

% 

80.896 

520.77 

% 

105.636 

888.00 

18. 

56.549 

254.47 

% 

81.289 

525.84 

% 

106.029 

894.62 

ys 

56.941 

258.02 

26. 

81.681 

530.93 

% 

106.421 

901.26 

2 

57.334 

261.59 

y» 

82.074 

536.05 

34. 

106.814 

907.92 

% 

57.727 

265.18 

% 

82.467 

541.19 

tt 

107.207 

914.61 

Vz 

58.119 

268.80 

% 

82.860 

546.35 

y* 

107.600 

921.32 

% 

58.512 

272.45 

% 

83.252 

551.55 

% 

107.992 

928.06 

% 

58.905 

276.12 

83.645 

556.76 

Vz 

108.385 

934.82 

7/8 

59.298 

279.81 

84.038 

562.00 

% 

108.778 

941.61 

19. 

59.690 

283.53 

% 

84.430 

567.27 

% 

109.170 

948.42 

% 

60.083 

287.27 

27. 

84.823 

572.56 

% 

109.563 

955.25 

2 

60.476 

291.04 

Vs 

85.216 

577.87 

35. 

109.956 

962.11 

% 

60.868 

294.83 

% 

85.608 

583.21 

ys 

110.348 

969.00 

3 

61.261 

298.65 

% 

86.001 

588.57 

y4 

110.741 

975.91 

61.654 

302.49 

Vz 

86.394 

593.96 

% 

111.134 

982.84 

62.046 

306.35 

% 

86.786 

599.37 

y2 

111.527 

989.80 

% 

62.439 

310.24 

% 

87.179 

604.81 

% 

111.919 

996.78 

30. 

62.832 

314.16 

7/8 

87.572 

610.27 

% 

112.312 

1003.8 

^ 

63.225 

318.10 

28. 

87.965 

615.75 

% 

112.705 

1010.8 

$ 

63.617 

322.06 

¥s 

88.357 

621.26 

36. 

113.097 

1017.9 

% 

64.010 

326.05 

% 

88.750 

626.80 

ys 

113.490 

1025.0 

i 

64.403 
64.795 

330.06 
334.10 

% 

Va 

89.143 
89.535 

632.36 
637.94 

1 

113.883 
114.275 

1032.1 
1039.2 

% 

65.188 

338.16 

% 

89.928 

643.55 

114.668 

1046.3 

% 

65.581 

342.25 

% 

90.321 

649.18 

% 

115.061 

1053.5 

21. 

65.973 

346.36 

% 

90.713 

654.84 

% 

115.454 

1060.7 

% 

66.366 

350.50 

29. 

91.106 

660.52 

% 

115.846 

1068.0 

V* 

66.759 

354.66 

Vs 

91.499 

666.23 

37. 

116.239 

1075.2 

% 

67.152 

358.84 

% 

91.892 

671.96 

ys 

116.632 

1082.5 

67.544 

363.05 

% 

92.284 

677.71 

y* 

117.024 

1089.8 

5^ 

67.937 

367.28 

ya 

92.677 

683.49 

% 

117.417 

1097.1 

% 

68.330 

371.54 

93.070 

689.30 

y2 

117.810 

1104.5 

% 

68.722 

375.83 

93.462 

695  13 

% 

118.202 

1111.8 

32. 

69.115 

380.13 

7/8 

93.855 

700.98 

% 

118.596 

1119.2 

y8 

69.508 

384.46 

30. 

94.248 

706.86 

7/8        118.988 

1126.7 

Reprinted  by  permission  from  "Kent's  Mechanical  Engineers'  Pocket  Book" 


ELECTRIC  INTERLOCKING  HANDBOOK 


399 


Diam. 

Circum. 

Area 

Diam. 

Circum. 

Area 

Diam. 

Circum. 

Area 

38. 

119.381 

1134.1 

45% 

144.121 

1652.9 

538/4 

168.861 

2269.1 

ft 

119.773 

1141.6 

46. 

144.513 

1661.9 

% 

169.253 

2279.6 

% 

120.166 

1149.1 

Vs 

144.906 

1670.9 

54. 

169.646 

2290.2 

% 

120.559 

1156.6 

H 

145.299 

1680.0 

% 

170.039 

2300.8 

Va 

120.951 

1164.2 

% 

145.691 

1689.1 

V4 

170.431 

2311.5 

% 

121.344 

1171.7 

Va 

146.084 

1698.2 

% 

170.824 

2322.1 

% 

121.737 

1179.3 

% 

146.477 

1707.4 

Va 

171.217 

2332.8 

% 

122.129 

1186.9 

94 

146.869 

1716.5 

% 

171.609 

2343.5 

39. 

122.522 

1194.6 

7/8 

147.262 

1725.7 

% 

172.002 

2354.3 

Vs 

122.915 

1202.3 

47.  f 

147.655 

1734.9 

% 

172.395 

2365.0 

% 

123.308 

1210.0 

148.048 

1744.2 

55. 

172.788 

2375.8 

% 

123.700 

1217.7 

14 

148.440 

1753.5 

Vs 

173.180 

2386.6 

Va 

124.093 

1225.4 

% 

148.833 

1762.7 

% 

173.573 

2397.5 

% 

124.486 

1233.2 

•}/„ 

149.226 

1772.1 

% 

173.966 

2408.3 

§4 

124.878 

1241.0 

149.618 

1781.4 

y2 

174.358 

2419.2 

7/8 

125.271 

1248.8 

150.011 

1790.8 

% 

174.751 

2430.1 

40. 

125.664 

1256.6 

7/8 

150.404 

1800.1 

% 

175.144 

2441.1 

Vs 

126.056 

1264.5 

48. 

150.796 

1809.6 

7/8 

175.536 

2452.0 

V4 

126.449 

1272.4 

Vs 

151.189 

1819.0 

56. 

175.929 

2463.0 

% 

126.842 

1280.3 

% 

151.582 

1828.5 

% 

176.322 

2474.0 

Vz 

127.235 

1288.2 

% 

151.975 

1837.9 

J/4 

176.715 

2485.0 

% 

127.627 

1296.2 

Va 

152.367 

1847.5 

% 

177.107 

2496.1 

' 

128.020 

1304.2 

% 

152.760 

1857.0 

y2 

177.500 

2507.2 

*V& 

128.413 

1312.2 

% 

153.153 

1866.5 

177.893 

2518.3 

41. 

128.805 

1320.3 

7/8 

153.545 

1876.1 

178.285 

2529.4 

% 

129.198 

1328.3 

49. 

153.938 

1885.7 

7/8 

178.678 

2540.6 

5 

129.591 

1336.4 

Vs 

154.331 

1895.4 

57. 

179.071 

2551.8 

% 

129.983 

1344.5 

Yi 

154.723 

1905.0 

% 

179.463 

2563.0 

¥> 

130.376 

1352.7 

% 

155.116 

1914.7 

V4 

179.856 

2574.2 

5/8 

130.769 

1360.8 

Va 

155.509 

1924.4 

% 

180.249 

2585.4 

% 

131.161 

1369.0 

% 

155.902 

1934.2 

Va 

180.642 

2596.7 

7/8 

131.554 

1377.2 

8/4 

156.294 

1943.9 

% 

181.034 

2608.0 

43. 

131.947 

1385.4 

7/8 

156.687 

1953.7 

% 

181.427 

2619.4 

Vs 

132.340 

1393.7 

50. 

157.080 

1963.5 

% 

181.820 

2630.7 

ft 

132.732 

1402.0 

% 

157.472 

1973.3 

58. 

182.212 

2642.1 

% 

133.125 

1410.3 

y* 

157.865 

1983.2 

Vs 

182.605 

2653.5 

Va 

133.518 

1418.6 

% 

158.258 

1993.1 

V4 

182.998 

2664.9 

% 

133.910 

1427.0 

Va 

158.650 

2003.0 

% 

183.390 

2676.4 

% 

134.303 

1435.4 

% 

159.043 

2012.9 

Va 

183.783 

2687.8 

7/8 

134.696 

1443.8 

% 

159.436 

2022.8 

% 

184.176 

2699.3 

43. 

135.088 

1452.2 

% 

159.829 

2032.8 

% 

184.569 

2710.9 

Vs 

135.481 

1460.7 

51. 

160.221 

2042.8 

7/8 

184.961 

2722.4 

% 

135.874 

1469.1 

Vs 

160.614 

2052.8 

59. 

185.354 

2734.0 

% 

136.267 

1477.6 

^4 

161.007 

2062.9 

% 

185.747 

2745.6 

% 

136.659 

1486.2 

8/8 

161.399 

2073.0 

V4 

186.139 

2757.2 

% 

137.052 

1494.7 

1/2 

161.792 

2083.1 

% 

186.532 

2768.8 

% 

137.445 

1503.3 

162.185 

2093.2 

Va 

186.925 

2780.5 

7/8 

137.837 

1511.9 

162.577 

2103.3 

187.317 

2792.2 

44. 

138.230 

1520.5 

7/8 

162.970 

2113.5 

187.710 

2803.9 

Vs 

138.623 

1529.2 

52. 

163.363 

2123.7 

188.103 

2815.7 

y* 

139.015 

1537.9 

% 

163.756 

2133.9 

60. 

188.496 

2827.4 

% 

139.408 

1546.6 

V4 

164.148 

2144.2 

Vs 

188.888 

2839.2 

% 

139.801 

1555.3 

% 

164.541 

2154.5 

$4 

189.281 

2851.0 

% 

140.194 

1564.0 

ft 

164.934 

2164.8 

% 

189.674 

2862.9 

% 

140.586 

1572.8 

165.326 

2175.1 

y3 

190.066 

2874.8 

7/8 

140.979 

1581.6 

165.719 

2185.4 

% 

190.459 

2886.6 

45. 

141.372 

1590.4 

7/8 

166.112 

2195.8 

% 

190.852 

2898.6 

% 

141.764 

1599.3 

53. 

166.504 

2206.2 

% 

191.244 

2910.5 

Vt 

142.157 

1608.2 

Vs 

166.897 

2216.6 

61. 

191.637 

2922.5 

% 

142.550 

1617.0 

167.290 

2227.0 

Vs 

192.030 

2934.5 

Va 

142.942 

1626.0 

% 

167.683 

2237.5 

V4 

192.423 

2946.5 

% 

143.335 

1634.9 

I/. 

168.075 

2248.0 

% 

192.815 

2958.5 

% 

143.728 

1643.9 

% 

168.468 

2258.5 

Va 

193.208 

2970.6 

Reprinted  by  permission  from  "Kent's  Mechanical  Engineers'  Pocket  Book." 


400 


GENERAL  RAILWAY  SIGNAL  COMPANY 


Diam. 

Circum. 

Area 

Diam. 

Circum. 

Area 

Diam. 

Circum.       Area 

61% 

193.601 

2982.7 

69y2 

218.341 

3793.7 

77% 

243.081     4702.1 

193.993 

2994.8 

% 

218.733 

3807.3 

V2 

243.473     4717.3 

% 

194.386    3006.9 

% 

219.126 

3821.0 

243.866     4732.5 

62. 

194.779i  3019.1 

% 

219.519 

3834.7 

8/4 

244.259     4747.8 

195.171 

3031.3 

70. 

219.911 

3848.5 

244.652  ;  4763.1 

V± 

195.564 

3043.5' 

220.304 

3862.2 

78? 

245.044 

4778.4 

% 

195.957 

3055.7 

•V4 

220.697 

3876.0 

Ys 

245.437 

4793.7 

196.350 

3068.0 

% 

221.090 

3889.8 

245.830 

4809.0 

196.742 

3080.3 

Vz 

221.482 

3903.6 

% 

246.222 

4824.4 

197.135 

3092.6 

% 

221.875 

3917.5 

¥2 

246.615 

4839.8 

7/8 

197.528 

3104.9 

94 

222.268 

3931.4 

247.008 

4855.2 

63. 

197.920 

3117.2 

7/8 

222.660 

3945.3 

247.400 

4870.7 

Vs 

198.313 

3129.6 

71. 

223.053 

3959.2 

247.793 

4886.2 

V4 

198.706 

3142.0 

223.446 

3973.1 

79* 

248.186 

4901.7 

199.098 

3154.5 

-V4 

223.838 

3987.1 

Vs 

248.579 

4917.2 

V2 

199.491 

3166.9 

% 

224.231 

4001.1 

248.971 

4932.7 

199.884 

3179.4 

Va 

224.624 

4015.2 

% 

249.364 

4948.3 

% 

200.277 

3191.9 

225.017 

4029.2 

% 

249.757 

4963.9 

7/8 

200.669 

3204.4 

% 

225.409 

4043.3 

% 

250.149 

4979.5 

64. 

201.062 

3217.0 

7/8 

225.802 

4057.4 

% 

250.542 

4995.2 

201.455 

3229.6 

73. 

226.195 

4071.5 

% 

250.935 

5010.9 

5 

201.847 

3242.2 

H 

226.587 

4085.7 

80. 

251.327 

5026.5 

202.240 

3254.8 

226.980 

4099.8 

251.720 

5042.3 

% 

202.633 

3267.5 

% 

227.373 

4114.0 

^4 

252.113 

5058.0 

203.025 

3280.1 

227.765 

4128.2 

% 

252.506 

5073.8 

% 

203.418 

3292.8 

228.158 

4142.5 

¥2 

252.898 

5089.6 

7& 

203.811 

3305.6 

228.551 

4156.8 

253.291 

5105.4 

65. 

204.204 

3318.3 

7/8 

228.944 

4171.1 

% 

253.684 

5121.2 

204.596 

3331.1 

73. 

229.336 

4185.4 

7/8 

254.076 

5137.1 

•V4 

204.989 

3343.9 

229.729 

4199.7 

81. 

254.469 

5153.0 

% 

205.382 

3356.7 

•y. 

230.122 

4214.1 

H 

254.862 

5168.9 

% 

205.774 

3369.6 

% 

230.514 

4228.5 

255.254 

5184.9 

206.167;  3382.4 

¥2 

230.907 

4242.9 

% 

255.647 

5200.8 

206.560   3395.3 

% 

231.300 

4257.4 

V2 

256.040 

5216.8 

206.952 

3408.2 

231.692 

4271.8 

256.433 

5232.8 

66. 

207.345 

3421.2 

% 

232.085 

4286.3 

SA 

256.825 

5248.9 

207.738 

3434.2 

74. 

232.478 

4300.8 

% 

257.218 

5264.9 

% 

208.131 

3447.2 

Ys 

232.871 

4315.4 

82^ 

257.611 

5281.0 

208.523    3460.2 

1/4 

233.263 

4329.9 

258.003 

5297.1 

|L 

208.916,  3473.2 

233.656 

4344.5 

258.396 

5313.3 

% 

209.309    3486.3 

Yz 

234.049 

4359.2 

258.789 

5329.4 

% 

209.701    3499.4 

% 

234.441 

4373.8 

% 

259.181 

5345.6 

7/8 

210.094   3512.5 

% 

234.834 

4388.5 

259.574 

5361.8 

67. 

210.487    3525.7 

7/8 

235.227 

4403.1 

% 

259.967 

5378.1 

Vs 

210.879   3538.8 

75. 

235.619 

4417.9 

7/8 

260.359 

5394.3 

211.272    3552.0 

% 

236.012 

4432.6 

83. 

260.752 

5410.6 

% 

211.665    3565.2 

y* 

236.405 

4447.4 

% 

261  .  145 

5426.9 

212.058 

3578.5 

236.798 

4462.2 

261.538 

5443.3 

% 

212.450 

3591.7 

¥2 

237.190 

4477.0 

% 

261.930 

5459.6 

% 

212.843 

3605.0 

237.583 

4491.8 

Yz 

262.323 

5476.0 

7/8 

213.236   3618.3 

237.976 

4506.7 

262.716 

5492.4 

68. 

213.628J  3631.7 

. 

238.368 

4521.5 

263.108 

5508.8 

214.021    3645.0 

76. 

238.761 

4536.5 

7/8 

263.501 

5525.3 

V4 

214.414    3658.4 

ft 

239.154 

4551.4 

84. 

263.894 

5541.8 

214.806   3671.8 

V4 

239.546 

4566.4 

ft 

264.286 

5558.3 

% 

215.199    3685.3 

239.939 

4581.3 

% 

264.679 

5574.8 

% 

215.592   3698.7 

14 

240.332 

4596.3 

265.072 

5591.4 

215.984    3712.2 

B8 

240.725 

4611.4 

1/L 

265.465 

5607.9 

% 

216.377   3725.7 

% 

241.117 

4626.4 

265.857 

5624.5 

69. 

216.770   3739.3 

% 

241.510 

4641.5 

266.250 

5641.2 

217.163    3752.8 

77. 

241.903 

4656.6 

1' 

266.643 

5657.8 

i/. 

217.555    3766.4 

242.295 

4671.8 

85./8 

267.035 

5674.5 

% 

217.948J  3780.0 

ft 

242.688 

4686.9 

Vs 

267.428 

5691.2 

Reprinted  by  permission  from  "Kent's  Mechanical  Engineers'  Pocket  Book." 


ELECTRIC   INTERLOCKING   HANDBOOK 


401 


Dlam. 

Circum. 

Area 

Dlam. 

Circum. 

Area 

Diam. 

Circum. 

Area 

85*4 

267.821 

5707.9 

90^4 

283.529 

6397.1 

95V4 

299.237 

7125.6 

% 

268.213 

5724.7 

% 

283.921 

6414.9 

% 

299.629 

7144.3 

s 

268.606 

5741.5 

284.314 

6432.6 

y2 

300.022 

7163.0 

% 

268.999 

5758.3 

284.707 

6450.4 

% 

300.415 

7181.8 

% 

269.392 

5775.1 

285.100 

6468.2 

% 

300.807 

7200.6 

7/8 

269.784 

5791.9 

% 

285.492 

6486.0 

.% 

301.200 

7219.4 

86. 

270.177 

5808.8 

91. 

285.885 

6503.9 

96. 

301.593 

7238.2 

Vs 

270.570 

5825.7 

286.278 

6521.8 

46 

301.986 

7257.1 

% 

270.962 

5842.6 

% 

286.670 

6539.7 

% 

302.378 

7276.0 

% 

271.355 

5859.6 

% 

287.063 

6557.6 

% 

302.771 

7294.9 

% 

271.748 

5876.5 

Vs 

287.456 

6575.5 

¥2 

303.164 

7313.8 

272.140 

5893.5 

% 

287.848 

6593.5 

% 

303.556 

7332.8 

94 

272.533 

5910.6 

% 

288.241 

6611.5 

% 

303.949 

7351.8 

% 

272.926 

5927.6 

% 

288.634 

6629.6 

7/8 

304.342 

7370.8 

87. 

273.319 

5944.7 

93. 

289.027 

6647.6 

97. 

304.734 

7389.8 

273.711 

5961.8 

Vs 

289.419 

6665.7 

% 

305.127 

7408.9 

i/ 

274.104 

5978.9 

% 

289.812 

6683.8 

% 

305.520 

7428.0 

% 

274.497 

5996.0 

% 

290.205 

6701.9 

% 

305.913 

7447.1 

Vfc 

274.889 

6013.2 

5 

290.597 

6720.1 

V2 

306.305 

7466.2 

275.282 

6030.4 

% 

290.990 

6738.2 

% 

306.698 

7485.3 

275.675 

6047.6 

% 

291.383 

6756.4 

tft 

307.091 

7504.5 

7/8 

276.067 

6064.9 

% 

291.775 

6774.7 

% 

307.483 

7523.7 

88. 

276.460 

6082.1 

93. 

292.168 

6792.9 

98. 

307.876 

7543.0 

Vs 

276.853 

6099.4 

292.561 

6811.2 

308.269 

7562.2 

^4 

277.246 

6116.7 

I/, 

292.954 

6829.5 

i^ 

308.661 

7581.5 

% 

277.638 

6134.1 

% 

293.346 

6847.8 

% 

309.054 

7600.8 

Va 

278.031 

6151.4 

% 

293.739 

6866.1 

•Vis 

309.447 

7620.1 

278.424 

6168.8 

% 

294.132 

6884.5 

% 

309.840 

7639.5 

278.816 

6186.2 

% 

294.524 

6902.9 

% 

310.232 

7658.9 

7/8 

279.209 

6203.7 

% 

294.917 

6921.3 

% 

310.625 

7678.3 

89. 

279.602 

6221.1 

94. 

295.310 

6939.8 

99. 

311.018 

7697.7 

Vs 

279.994 

6238.6 

44 

295.702 

6958.2 

% 

311.410 

7717.1 

% 

280.387 

6256.1 

% 

296.095 

6976.7 

V4 

311.803 

7736.6 

% 

280.780 

6273.7 

$ 

296.488 

6995.3 

312.196 

7756.1 

281.173 

6291.2 

¥2 

296.881 

7013.8 

312.588 

7775.6 

% 

281.565 

6308.8 

% 

297.273 

7032.4 

312.981 

7795.2 

% 

281.958 

6326.4 

% 

297.666 

7051.0 

% 

313.374 

7814.8 

% 

282.351 

6344.1 

% 

298.059 

7069.6 

% 

313.767 

7834.4 

90. 

282.743 

6361.7 

95. 

298.451 

7088.2 

100. 

314.159 

7854.0 

Vs 

283.136 

6379.4 

% 

298.844 

7106.9 

Reprinted  by  permission  from  "Kent's  Mechanical  Engineers'  Pocket  Book." 


SECTION    XVIII 


APPENDIX 


COVERING  REPRINT  OF  PREFACE 
FROM  TAYLOR  (G.  R.  S.)  CATALOGUE 
NO.  1,  INFORMATION  REQUIRED  FOR 
THE  DRAWING  UP  OF  INTERLOCKING 
ESTIMATES,  AND  A  LIST  OF  G.  R.  S. 
ELECTRIC  INTERLOCKING  LEVERS 
INSTALLED 


APPENDIX 


REPRINT  OF  PREFACE 

From  Catalogue  No.  1  (1902),  Taylor  Signal  Company,  Buffalo, 
N.  Y.  Taylor  Signal  Company  acquired  by  the  General  Rail- 
way Signal  Company  in  1904. 

IN  the  last  few  years  there  has  been  a  phenomenal  increase 
in  tonnage  hauled  on  American  railways,  necessitating 
the  purchase  of  more  and  better  engines  and  cars  of  larger 
capacity,  equipped  with  the  best  safety  devices.  Enor- 
mous sums  have  been  expended  in  taking  out  curves,  cutting 
down  grades,  laying  additional  main  tracks,  putting  in  new 
sidings,  and  providing  improved  terminal  facilities.  But, 
notwithstanding  all  these  improvements,  many  lines  find  it 
impossible  to  handle  their  business  with  sufficient  dispatch  to 
avoid  congestion.  This  fact  has  led  many  progressive  Ameri- 
can railway  managers  to  realize  that  if  they  are  to  secure  the 
best  and  most  economical  returns  from  the  great  expenditures 
made  for  motive  power,  car  equipment,  and  tracks,  suitable 
means  must  be  provided  to  enable  their  trains  to  move  with  a 
minimum  of  delays  and  a  maximum  of  safety;  and  this  can 
only  be  realized  when  train  orders  are  supplanted  by  an  up-to- 
date  block  system  and  hand  operated  switches  by  a  modern 
system  of  interlocking. 

The  very  highest  development  of  the  art  of  signaling  has 
been  reached  in  this  country,  but  no  American  railway  is  nearly 
so  thoroughly  equipped  with  signaling  as  is  the  average  English 
line. 

This  lack  of  signal  equipment  will  be  better  comprehended 
after  considering  some  simple  statistics. 

The  first  interlocking  plant  installed  on  the  London  and 
Northwestern  Railway  was  put  in  service  in  1859;  fourteen 
years  later,  in  1873,  there  were  in  use  on  that  line  alone  13,000 
levers.  At  the  same  date  there  was  not  a  single  interlocking 
plant  in  use  in  the  United  States,  the  first  plant  in  this  country 
having  been  installed  in  the  year  1874  by  Messrs.  Toucy  and 
Buchanan  at  Spuyten  Duyvil  Junction,  in  New  York  City. 

At  the  present  time  (1902)  there  are  in  use  on  the  1,800 
miles  of  line  of  the  London  and  Northwestern  Railway  ap- 
proximately 36,000  interlocked  levers,  or  an  average  of  about 
twenty  levers  per  mile  of  line,  whereas  there  are  only  about 
40,000  in  use  on  all  lines  of  the  United  States,  or,  approxi- 
mately, one  lever  to  five  miles  of  line,  or  about  1  'per  cent, 
of  the  number  of  levers  per  mile  used  on  the  London  and 
Northwestern  Railway. 

When  it  is  remembered  that  probably  more  than  one-half 
of  the  interlocked  levers  in  use  in  this  country  are  at  grade 
crossings,  leaving  fewer  than  20,000  levers  used  for  station, 
yard  and  terminal  work,  whereas  practically  the  entire  36,000 


406  GENERAL  RAILWAY  SIGNAL  COMPANY 


on  the  L.  &  N.  W.  are  used  for  such  work  alone,  it  will  be  recog- 
nized that  American  railways  are  in  general  very  poorly  pro- 
vided with  modern  signal  appliances.  In  fact,  there  is  probably 
to-day  not  a  single  American  railway  that  is  nearly  so  thor- 
oughly equipped  as  the  London  and  Northwestern  was  twenty- 
seven  years  ago,  though,  as  might  be  expected,  the  devices  in 
use  on  American  lines  haying  properly  organized  signal  depart- 
ments, capable  of  making  suitable  specifications,  compare 
favorably  with  the  best  in  use  on  European  lines  and,  in  nu- 
merous instances,  large  power  plants  are  in  use  which  are  supe- 
rior to  anything  ever  devised  abroad. 

There  can  be  no  question  as  to  the  inability  of  most  of  our 
railways  to  move  their  trains  with  proper  safety  and  dispatch 
during  times  when  traffic  is  heavy;  no  competent  railway 
operating  officer  doubts  that  proper  systems  of  signaling  would 
greatly  aid  in  the  safer  and  more  rapid  movement  of  trains 
and,  while  there  are  probably  few  American  railway  men 
who  recognize  fully  how  very  far  behind  the  best  European 
lines  our  lines  are  in  respect  to  the  completeness  of  their  signal 
equipment,  this  is  becoming  better  understood  every  year 
and  there  is  reason  to  believe  that  our  most  progressive  lines 
will  not  much  longer  continue  to  limit  the  applications  of 
interlocking  to  the  protection  of  grade  crossings  with  here 
and  there  a  junction  or  yard  plant. 

Such  being  the  case,  it  is  probable  that  more  signaling  will 
be  done  in  the  near  future  than  has  ever  before  been  done  in 
this  country  and  American  railway  managers  will,  therefore, 
find  it  greatly  to  their  advantage  to  give  serious  consideration 
to  the  determination  of  what  system  of  interlocking  they  can 
best  use. 

The  earliest  system  employed  and  that  in  most  general  use 
at  this  time  is  the  so-called  "mechanical  interlocking"  in 
which  the  switches  or  signals  are  manually  worked  by  means 
of  interlocked  levers  connected  with  them  by  pipe  or  wire  lines. 

When  properly  installed,  this  system  has  given  satisfactory 
results;  but,  unfortunately,  in  the  effort  of  railway  men  to 
secure  cheap  appliances  and  in  the  stress  of  competition  be- 
tween the  various  manufacturers  of  signaling  devices,  a  great 
many  of  the  installations  made  in  this  country  are  very  imper- 
fect and  unsafe. 

Experience  has  shown  that,  in  order  to  secure  a  reasonable 
degree  of  safety,  it  is  absolutely  essential  that  the  following 
requirements  be  met : 

All  derails,  movable  point  frogs,  locks,  switches  and  home 
signals  should  be  worked  by  pipe ;  no  signal  should  be  worked 
by  a  single  wire ;  all  pipe  and  wire  lines  should  be  automatic- 
ally compensated ;  all  derails,  movable  point  frogs  and  facing 
point  switches  should  be  provided  with  duplex  facing  point 
locks;  all  cranks  and  pipe  compensators  should  be  fixed  on 
strong  foundations  set  in  best  quality  concrete;  no  facing 
point  switch  more  than  600  feet  from  the  tower  should  be 


ELECTRIC  INTERLOCKING  HANDBOOK  407 


taken  into  the  system ;  no  lever  should  "be  overloaded  by 
putting  on  it  such  a  number  of  switches  and  bars  as  to  pre- 
vent a  man  of  average  strength  from  throwing  it  with  one 
hand. 

Where  these  and  other  proper  specifications  have  been  fol- 
lowed, fair  results  have  been  obtained,  though  it  has  long 
been  recognized  by  American  railway  operating  officials  that 
this  system  has  inherent  defects  that  render  it,  under  certain 
conditions,  unsafe.  For  example,  in  the  event  of  the  breakage 
of  a  pipe  or  wire  operating  a  signal,  there  can  be  no  absolute 
assurance  that  such  breakage  will  be  known  by  the  leverman 
or  that  such  signal  will  occupy  a  position  corresponding  with 
that  of  its  lever  or  that  it  will  not  indicate  "line  clear"  when, 
its  lever  being  normal,  another  and  opposing  signal  is  set  at 
"line  clear." 

The  fatigue  incident  to  working  mechanical  levers  is  very 
great,  so  that  it  is  frequently  necessary  to  employ  three  eight- 
hour  levermen  for  a  comparatively  small  plant  where  the 
number  of  lever  movements  is  considerable;  if  the  plant  is 
very  large,  it  is  sometimes  necessary  to  employ  as  many  as 
eight  men  on  each  of  three  shifts. 

Moreover,  under  certain  conditions  it  is  very  costly  to  operate 
such  a  system.  For  example,  in  cases  where  the  distance 
between  the  extreme  switches  to  be  operated  is  over  1,600 
feet,  it  is  generally  necessary  to  provide  two  mechanical  inter- 
locking towers,  each  with  its  own  set  of  levermen,  as  it  is 
neither  safe  nor  practicable  to  work  such  switches  from  one 
tower.  It  is  interesting  to  note  in  this  connection  that  under 
the  English  Board  of  Trade  requirements,  which  are  wisely 
drawn  and  rigidly  enforced,  no  facing  point  switch  may  be 
operated  at  a  distance  exceeding  540  feet  from  the  tower. 
Even  at  this  distance  it  is  considered  that  ordinary  pipe  lines 
are  not  sufficiently  strong  or  safe  and  many  English  lines  now 
employ  a  steel  channel  section,  cut  to  eighteen  foot  lengths  and 
jointed  by  means  of  fish  plates  secured  by  six  one-half  inch 
bolts,  this  construction  admitting  of  ready  detection  of  rods 
weakened  by  corrosion  and  of  their  easy  removal.- 

In  order  to  overcome  these  and  other  disadvantages  inherent 
in  systems  of  mechanical  interlocking,  the  "pneumatic  system  " 
was  devised  by  Mr.  George  Westinghouse,  Jr.,  the  first  working 
installation  having  been  made  at  the  crossing  of  the  P.  and  R. 
and  L.  V.  Railways,  near  Bound  Brook,  N.  J.,  in  1884. 

At  the  present  time  two  varieties  of  this  system  are  in  use, 
one,  popularly  known  as  the  "electro-pneumatic,"  in  which 
air  compressed  to  a  working  pressure  of  about  sixty  pounds 
is  employed  for  moving  switches  and  signals  and  in  which  the 
release  locking  is  effected  by  electro-magnetic  means ;  and  the 
other,  popularly  known  as  the  "low  pressure  pneumatic,"  in 
which  air  at  a  pressure  of  about  twenty  pounds  is  used  for 
operation  and  in  which  compressed  air  effects  the  release 
locking. 


408  GENERAL  RAILWAY  SIGNAL  COMPANY 


Some  of  the  advantages  claimed  for  this  system  are  as 
follows : 

The  ability  to  operate  switches  and  signals  at  any  desired 
distance  from  the  cabin ;  that  switches  are  actually  required 
to  be  moved  and  securely  locked  in  the  proper  position  before 
a  signal  governing  traffic  over  them  can  be  cleared ;  that  each 
signal,  when  cleared,  automatically  locks  the  lever  operating  it 
in  such  manner  as  to  prevent  the  release  of  levers  controlling 
conflicting  signals  and  switches,  until  such  signal  has  been 
again  placed  completely  at  danger,  thus  effectually  providing 
against  the  simultaneous  display  of  two  conflicting  clear 
signals;  that,  there  being  no  moving  parts  between  cabin 
and  switches  and  signals,  wear  of  mechanism,  lost  motion  and 
the  troublesome  and  dangerous  effects  of  expansion  and  con- 
traction of  mechanically  operated  pipes  and  wires  are  all 
eliminated;  that  much  less  room  is  required  for  leadout  con- 
nections than  in  a  mechanical  plant  and  much  valuable  space 
is  thereby  saved;  that  cabins  of  much  smaller  and  lighter 
design  are  used ;  that  the  operation  of  the  machine  requires  so 
little  physical  exertion  that  one  man  can  do  the  work  that 
would  in  a  mechanical  plant  require  three  or  four. 

There  can  be  no  doubt  that  both  varieties  of  the  pneumatic 
system  are  far  better  adapted  for  the  working  of  large  plants 
than  the  mechanical  as  both  largely  fulfill  the  claims  above 
referred  to. 

It  is,  however,  found  that  in  the  electro-pneumatic  system 
a  cross  between  the  release  locking  (commonly  known  as  "indi- 
cation") wire  and  the  common  return  wire  (or  ground),  will 
have  the  same  effect  as  would  the  closing  of  the  indication  cir- 
cuit in  the  proper  manner,  thus  giving  a  false  indication,  which 
in  view  of  the  fact  that  the  safety  of  any  power  interlocking 
depends  upon  the  reliability  of  its  indications,  is  highly  objec- 
tionable. It  is  also  found  that  where  the  indication  is  given 
by  means  of  compressed  air  the  release  locking  is  often  effected 
very  slowly  in  cases  where  switches  or  signals  are  located  at  a 
considerable  distance  from  the  tower  and  this,  at  a  busy  plant, 
is  also  very  objectionable. 

Another  disadvantage  of  the  low  pressure  pneumatic  system 
is  that  if  a  switch,  meeting  any  obstruction,  fails  to  complete 
its  movement  and  to  give  indication,  it  is  necessary  either  for 
a  repairman  to  go  immediately  to  the  switch  and  operate  it 
by  hand  or  for  the  leverman  to  force  the  indication,  which  is 
often  done  and  is  evidently  dangerous.  Thus,  in  one  style  of 
the  pneumatic  system  there  is  the  defect  due  to  possibility  of 
false  indication  and  in  the  other  the  defect  due  to  slow  indi- 
cation and  to  inability  to  reverse  a  switch  which  has  not  fully 
completed  its  movement.  Some  other  disadvantages  of  the 
pneumatic  systems  are  as  follows : 

Liability  to  freezing  of  pipes  and  valves  in  extreme  cold 
weather;  high  cost  of  furnishing  power;  danger  of  throwing 
near  switches  under  trains  when,  owing  to  extreme  cold 


ELECTRIC  INTERLOCKING  HANDBOOK  409 


weather,  it  is  necessary  to  maintain  higher  than  normal  pres- 
sures in  order  to  be  able  to  work  switches  farthest  from  tower  ; 
high  cost  of  maintenance  owing  to  rapid  deterioration  of  iron 
pipe  lines  placed  underground  and  subjected  to  action  of 
various  salts  and  alkalies  found  in  soil  and  to  electrolytic 
action  from  electric  railway  and  lighting  circuits;  difficulty 
and  cost  of  locating  leaks  and  breaks  in  pipe  lines  under  ground ; 
extremely  high  cost  of  installing  and  operating  medium  sized 
and  small  plants  or  a  small  number  of  switches  or  signals 
located  at  a  considerable  distance  from  the  tower  in  a  large 
plant. 

To  overcome  these  and  other  objectionable  features  of  the 
pneumatic  system,  the  "electric"  system  was  devised. 

This  system,  the  invention  of  Mr.  John  D.  Taylor  of  Chilli- 
cothe,  Ohio,  was  first  installed  by  him  on  the  B.  &  O.  S.  W. 
R'y  at  East  Norwood,  near  Cincinnati,  Ohio,  in  1891 ;  in 
1893  certain  improvements  were  introduced  by  him  in  the 
methods  of  giving  indications,  the  installation  remaining 
otherwise  as  originally  made.  For  some  years  afte~  1893, 
only  a  few  small  installations  were  made  by  Mr.  Taylo"  owing 
to  lack  of  sufficient  capital  to  develop  his  inventions  on  a 
large  scale,  but  in  May,  1900,  the  Taylor  Signal  Company  was 
organized  in  Buffalo,  N.  Y.,  and  since  that  time  a  great  number 
of  installations,  varying  in  size  from  the  equivalent  of  6  to  225 
mechanical  levers,  have  been  made  on  important  lines  of 
railway  in  the  United  States  and  Europe. 

In  the  Taylor  (G.  R.  S.)  electric  system,  switches  and  signals 
are  operated  by  means  of  electric  motors,  the  current  for 
these  motors  being  furnished  generally  by  a  storage  battery, 
charged  from  a  dynamo  driven  by  an  electric  motor  or  gas 
engine.  The  release  locking  is  effected  by  an  electro-magnetic 
device  placed  under  each  interlocking  lever  and  actuated  by 
a  dynamic  current  furnished  by  the  switch  or  signal  motor 
controlled  by  such  lever,  when  and  only  when  a  switch  has 
moved  to  a  position  corresponding  with  that  of  the  lever  and  is 
bolt  locked  in  that  position  or  when  a  signal  arm  has  moved  to  its 
full  danger  position.  Crosses  between  an  indication  wire  and 
common  return  wire  (or  ground)  or  any  other  wire  of  the 
system,  can  at  worst  only  prevent  the  giving  of  indication  and 
cannot  by  any  possibility  result  in  the  giving  of  a  false  clear 
indication  as  can  occur  in  other  systems  employing  electro- 
magnetic indications.  Moreover,  in  this  system,  indications 
are  given  instantaneously  upon  completion  of  locking  of  switch 
or  of  movement  of  signal  to  its  stop  position,  irrespective  of 
the  distance  of  such  switch  or  signal  from  the  tower,  thus 
effecting  a  great  saving  in  the  time  required  by  any  system 
using  pneumatic  indications,  to  set  up  a  route. 

If,  when  a  switch  is  thrown,  it  fails  to  complete  its  move- 
ment owing  to  some  obstruction  between  point  and  stock 
rail,  or  for  any  cause  whatever,  the  switch  can  be  restored  by 
the  leverman  to  its  original  position  and  another  effort  can 


410 


GENERAL  RAILWAY  SIGNAL  COMPANY 


be  made  to  perform  the  desired  movement,  ofttimes  thus 
avoiding  the  necessity,  so  frequently  met  with  in  the  low 
pressure  pneumatic  system,  of  sending  a  man  out  to  throw 
the  switch  by  hand  or  of  forcing  the  indication. 

The  electric  is  the  only  power  system  that  can  be  satisfac- 
torily employed  for  the  operation  of  plants  having  a  small 
number  of  switches  and  signals.  It  is  in  service  where  as  few 
as  six  working  levers  are  employed  and  is  perfectly  adapted 
for  use  at  all  junctions,  crossings,  drawbridges,  tunnels,  sta- 
tions, yards,  passing  sidings,  etc.,  where  the  distance  between 
extreme  switches  or  signals  is  greater  than  can  be  safely 
covered  with  a  mechanical  plant,  even  though  there  be  only  a 
very  few  signals  and  switches  to  be  operated.  For  example, 
consider  the  two  following  diagrams,  the  first  one  showing 
arrangement  of  passing  sidings  on  a  single  track  and  the  other 
on  a  double  track  line : 


1000167000 


1000  to  7000 


STATION-A 


1000  To  7000' 


1000  to  7000 
tL, 


'  iJ  6  d 


(GRS-1913) 


STATION* 


On  a  few  of  the  best  signaled  American  railways  the  switches 
and  signals  immediately  adjacent  to  the  station  A  or  B,  would 
be  worked  by  a  mechanical  interlocking  plant,  but  owing  to 
the  great  cost  of  operating  an  additional  mechanical  interlock- 
ing plant  at  each  of  the  extreme  switches  and  the  prohibitive 
cost  of  putting  in  a  pneumatic  power  system  by  which  all  the 
switches  and  signals  could  be  worked  from  the  station,  the 
inlet  switches  are  left  to  be  worked  by  the  trainmen,  necessi- 
tating the  stopping  of  their  trains;  and  if,  as  sometimes 
happens,  such  stoppage  occurs  on  a  bad  grade,  heavy  trains 
may  break  in  two  in  starting  up.  Every  practical  railway 
man  will  at  once  recognize  the  tremendous  advantage  that 
would  be  gained  if  these  extreme  switches,  together  with  their 
proper  signals,  could  be  safely  and  economically  worked  from 


ELECTRIC  INTERLOCKING  HANDBOOK  411 


the  station,  thereby  enabling  trains  to  pass  onto  and  out  of 
passing  sidings  at  speed  and  in  absolute  safety.  With  the 
Taylor  (G.  R.  S.)  electric  system  this  can  be  effected  at  a  rela- 
tively small  cost,  and,  in  conjunction  with  a  system  of  auto- 
matic, electric,  track  circuit  block  signals  in  use  on  the  open 
road,  where  there  are  no  switches,  this  forms  the  ideal  lock 
and  block  system  and  one,  which  we  believe  is  destined  to 
replace  all  others  both  in  this  country  and  in  Europe. 

In  the  electric  system,  the  cost  of  producing  power  for  the 
operation  of  switches  and  signals  rarely  or  never  exceeds 
1  per  cent,  of  the  cost  in  any  other  power  system  doing  an 
equal  amount  of  work.  For  example,  if  in  a  system  using 
compressed  air,  the  cost  of  coal  and  services  of  men  employed 
in  running  power  plant  is  400  dollars  per  month,  the  total  cost 
of  producing  power  for  an  electric  plant  doing  precisely  the 
same  work  will  rarely  or  never  exceed  four  dollars  monthly. 

In  this  connection  it  will  be  interesting  to  note  that  at  the 
South  Englewood  Taylor  (G.  R.  S.)  interlocking  plant  on  the 
C.  R.  I.  &  P.  R.  R.,  where  the  average  daily  number  of  switches 
moved  and  signals  cleared  is  2,250,  the  consumption  of  gaso- 
line for  running  engine  for  charging  storage  batteries,  was 
sixty-eight  gallons  in  eighty-six  days,  or  one  gallon  for  2,845 
switch  and  signal  operations.  At  Sixteenth  and  Clark  streets, 
Chicago,  Taylor  (G.  R.  S.)  interlocking  plant  at  the  crossing 
of  the  St.  Charles  Air  Line  with  the  C.  R.  I.  &  P.  and  L.  S.  & 
M.  S.  R'ys,  where  the  movement  exceeds  600  trains  daily,  the 
consumption  of  gasoline  during  153  days  was  222  gallons  for 
642,600  switch  and  signal  movements  or  2,894  per  gallon  or 
about  326  movements  for  one  cent  for  power. 

The  cost  of  maintenance  and  renewals  in  an  electric  plant 
is  only  a  small  percentage  of  the  cost  in  any  other  power  plant. 
This  can  be  readily  understood  from  the  fact  that  more  feet  of 
electrical  conductors  are  employed  in  the  electro-pneumatic 
system  than  are  used  in  the  Taylor  (G.  R.  S.)  system  and  there 
are  all  the  pneumatic  pipes;  and,  in  the  low  pressure  pneu- 
matic system,  more  feet  of  iron  pipe  are  used  than  feet  of  elec- 
tric conductors  in  the  Taylor  (G.  R.  S.)  system,  and  any  one 
having  experience  with  the  rapid  deterioration  of  iron  pipes 
placed  in  the  soils  found  about  railways  and  subject  to  elec- 
trolysis, will  have  no  difficulty  in  understanding  how  much 
shorter  lived  these  underground  pipes  will  be  than  well  insulated 
copper  wires  placed  in  a  suitable  conduit  above  ground.  Nor 
is  it  hard  to  understand  how  much  more  difficult  and  costly  it 
will  be  to  make  repairs  to  such  pipe  placed  several  feet  under^ 
ground  than  it  will  be  to  repair  a  break  or  leak  in  a  wire  placed 
in  a  suitable  conduit  above  ground. 

In  this  connection,  it  is  interesting  to  note  that  the  B.  &  O. 
S.  W.  R.  R.,  which  was  the  first  to  install  the  Taylor  (G.  R.  S.) 
system,  has  found  it  far  cheaper  to  maintain  than  an  ordinary 


mechanical  plant,  and  this  is  particularly  true  where,  through 
change  in   grade  or  alignment   of  tracks, 


any  changes  are 


412  GENERAL  RAILWAY  SIGNAL  COMPANY 


required  in  the  interlocking  plant,  such  changes  being  many 
times  more  costly  in  any  other  system  than  in  the  Taylor 
(G.  R.  S.)  electric.  Moreover,  with  the  improved  devices  and 
methods  of  installation  now  used  in  this  system,  a  far  better 
showing  will  be  made. 

The  operation  of  the  electric  system  is  absolutely  unaffected 
by  change  in  temperature,  whereas  pneumatic  systems  some- 
times experience  serious  difficulties  owing  to  condensation 
and  freezing  of  moisture  contained  in  the  compressed  air,  by 
which  the  mechanism  becomes  clogged  and  its  working  pre- 
vented. 

Even  where  the  working  is  not  absolutely  prevented  under 
these  conditions,  it  frequently  becomes  necessary  to  raise  the 
pressure  so  high  in  order  to  compensate  for  losses  in  pressure 
at  distant  switches,  that  there  is  danger  of  throwing  near 
switches  under  train,  in  case  leverman  makes  an  improper 
movement  at  such  a  time,  as  it  is  certain  that  as  generally 
installed,  detector  bar  connections  are  not  sufficiently  strong 
to  resist  any  considerable  increase  above  the  normal  working 
pressure  in  a  pneumatic  plant.  It  is  therefore  doubtful 
whether,  during  extreme  cold  weather,  it  is  ever  safe  to  attempt 
to  work  from  one  pneumatic  machine,  switches  and  signal, 
located  so  far  from  the  tower  as  to  require  any  increase  over 
normal  working  pressure.  Unquestionably,  the  safer  practice, 
at  such  times,  is  to  temporarily  abandon  the  working  of  such 
switches  and  signals,  as  is  often  done,  though  this,  of  course, 
causes  much  troublesome  delay  and  expense. 

In  the  electric  system  no  such  condition  exists,  as  the 
"electric  pressure"  is  exactly  the  same  on  the  switch  or  signal 
motor  located  at  a  distance  of  5,000  feet  as  on  one  located 
500  feet  from  the  tower;  moreover,  the  system  is  so  arranged 
that  the  throwing  of  a  switch  lever  while  train  is  over  the 
switch  would  cause  the  blowing  of  a  fuse  on  the  machine, 
thereby  opening  the  circuit. 

In  the  foregoing  statement  no  effort  has  been  made  to  de- 
scribe in  detail  the  appliances  and  circuits  employed  in  the 
Taylor  (G.  R.  S.)  electric  system  of  interlocking;  pur  object 
has  been  solely  to  point  out  the  need  of  signal  equipment  on 
American  railways  and  to  state,  without  prejudice,  the  prin- 
cipal merits  and  defects  of  the  several  interlocking  systems  at 
present  employed,  in  order  to  aid  such  railway  officials  as  have 
not  had  opportunity  to  acquaint  themselves  with  the  facts 
above  set  forth  to  make  an  intelligent  comparison  between 
such  systems. 

The  Taylor  (G.  R.  S.)  electric  system  is  in  the  fullest  accord 
with  modern  engineering  practice  which  has  shown,  after  years 
of  experiment,  that  transmission  of  power  to  a  distance  can 
be  more  satisfactorily  accomplithed  by  means  of  electricity 
than  by  any  other  agency  and,  while  there  is  no  reason  to 
doubt  that  this  system  will  be  improved  in  the  future  as  in 
the  past,  we  feel  warranted  in  claiming  at  the  present  time 


ELECTRIC  INTERLOCKING  HANDBOOK  413 

that  it  represents  the  very  highest  development  of  the  art  of 
signaling,  embodying  features  of  safety,  economy  and  general 
applicability  not  possessed  by  any  other  system  in  use  in  this 
country  or  abroad. 

TAYLOR  SIGNAL  COMPANY. 
(GENERAL  RAILWAY  SIGNAL  COMPANY.) 


INFORMATION    TO    BE    FURNISHED    BY    THE 

RAILWAY  COMPANY  WHEN  REQUESTING  AN 

ESTIMATE  ON  ELECTRIC  INTERLOCKING 

In  order  to  prepare  promptly  an  accurate  estimate  on  a  pro- 
posed installation  of  electric  interlocking,  it  is  necessary  that 
definite  information  on  certain  items  be  furnished  by  the  Rail- 
way Company  with  the  request  for  a  proposal.  This  informa- 
tion can  best  be  covered  by  a  specification  together  with 
certain  plans. 

It  is  not  necessary  for  each  individual  railroad  to  prepare  a 
specification  form  as  the  Railway  Signal  Association  adopted, 
in  1910,  a  very  complete  specification  covering  this  practice. 
The  specification  has  been  prepared  by  a  committee  of  men, 
actively  engaged  in  railway  signal  work,  and  its  use  is  heartily 
recommended.  It  can  be  secured  by  reference  to  the  Manual 
of  the  Railway  Signal  Association  issued  in  1912.  It  has,  of 
course,  been  necessary  in  drawing  up  this  specification  to 
leave  optional  a  number  of  items,  definite  information  on 
which  should  be  given  with  each  request  for  an  estimate. 
Attention  is  especially  directed  to  certain  points  essential 
to  the  preparation  of  estimates,  covered  by  sections  of  the 
specification  as  follows : 

3.     "Drawings." 

A  track  plan  should  be  furnished  giving  very  completely  the 
information  under  sub-paragraph  1.  The  symbols  which  have 
been  adopted  by  the  Railway  Signal  Association  as  shown  on 
pages  348  to  359  of  this  Handbook  should  be  used.  The  infor- 
mation called  for  in  sub-paragraphs  2,  3  and  4  should  be  given 
if  possible,  although  this  is  not  absolutely  necessary. 

7.  "Materials  to  be  furnished  and  work  to  be  done  by  and  at 

the  expense  of  the  Purchaser." 

Consideration  should  be  given  to  the  items  listed  in  this 
paragraph  and  note  made  of  any  deviation  therefrom. 

18.  "Transportation." 

A  definite  statement  should  be  made  as  to  whether  trans- 
portation is  to  be  furnished  for  men,  tools  and  materials  or  for 
either. 


414  GENERAL  RAILWAY  SIGNAL  COMPANY 


50.  "Building  foundations." 

51.  "Interlocking  station." 

52.  "Powerhouse." 

It  should  be  clearly  stated  whether  the  contractor  is  to 
erect  the  buildings  and  their  foundations,  the  dimensions  and 
specifications  being  given  if  such  is  the  case. 

54.  "Lighting  for  buildings." 

When  electric  lighting  for  any  of  the  buildings  is  desired, 
paragraphs  a,  b,  c  and  d  should  be  filled  out. 

60.  "Plant."  (Power  Plant.} 

61.  "Engine." 
70.  "Motor." 

85.  "Storage  battery." 

Definite  information  must  be  given  as  to  the  power  supply. 
The  ampere  hour  capacity  and  number  of  cells  of  the  battery 
should  be  specified  as  well  as  the  capacity  of  any  charging 
apparatus  desired.  Data  on  pages  154  to  159  of  this  Handbook 
will  be  of  assistance  in  determining  the  proper  capacities  for 
the  battery  and  charging  apparatus. 

100.  "Machine."  (Interlocking  Machine.) 

While  a  properly  prepared  track  plan  will  determine  the 
size  and  arrangement  of  levers  in  the  interlocking  machine,  it 
will  be  necessary  to  specify  any  spare  spaces  or  spare  levers 
required  in  the  event  of  this  information  not  being  shown  on 
the  plan. 

502.  "Track  circuits." 

The  number  and  arrangement  of  track  circuits  to  be  installed 
should  be  shown  on  the  plans  or  covered  in  the  specification. 

506.  "Electric  lighting  circuits" 

The  information  called  for  in  this  section  should  be  given, 
attention  being  called  to  pages  127  to  130  in  this  Handbook. 

510.  "Special  circuits." 

Typical  plans  of  special  circuits  may  be  furnished  under 
this  section  or  the  circuit  requirements  stated,  in  which  event 
the  contractor  will  submit  typical  proposed  circuits  with  the 
estimate.  Pages  133  to  139  of  this  Handbook  are  devoted  to 
Electric  Locking  circuits,  the  data  being  based  on  the  R.  S.  A. 
classification  of  the  different  types  of  circuits. 

521.  "Size."  (Wire  and  Wiring.} 

The  data  as  to  size  of  wires  under  paragraph  "  f  "  should  be 
given  when  track  circuits  are  to  be  installed. 


ELECTRIC  INTERLOCKING  HANDBOOK  415 

ELECTRIC   INTERLOCKING   LEVERS   INSTALLED 

AND   UNDER  CONTRACT 

JANUARY  1,  1913 

Number  Total 

Name  of  Road                                                            of  Plants  Levers 

Atchinson,  Topeka  &  Santa  Fe  R'y, 40  1348 

Atlanta,  Birmingham  &  Atlantic  R'y, 1  48 

Atlanta  Terminal  Station, 2  184 

Baltimore  &  Ohio, 19  880 

Birmingham  Terminal  Station, 1  144 

Buffalo  Creek  R.  R., 1  84 

Canadian  Pacific  R'y, 3  40 

Central  of  Georgia  R'y 1  52 

Central  R.  R.  of  New  Jersey, "1  28 

Chattanooga  Union  Station  Co., 1  120 

Chesapeake  &  Ohio  R'y, 7  212 

Chicago  &  Alton  R.  R., 2  108 

Chicago  &  Eastern  Illinois  R.  R., 4  136 

Chicago  &  Milwaukee  Electric,    ........       1  32 

Chicago  &  Northwestern  R'y, 35  2100 

Chicago  &  Western  Indiana  R.  R., 1  24 

Chicago,  Burlington  &  Quincy  R.  R., 7  464 

Chicago  Great  Western  R.  R., 5  128 

Chicago,  Indianapolis  &  Louisville  R'y  (Monon),        1  28 

Chicago,  Milwaukee  &  St.  Paul  R'y, 10  416 

Chicago,  Rock  Island  &  Pacific  R'y, 5  494 

Chicago,  St.  Paul,  Minneapolis  &  Omaha  R'y,     .       5  80 

Cincinnati,  New  Orleans  &  Texas  Pacific  R'y, .    .       6  208 

Cleveland,  Cincinnati,  Chicago  &  St.  Louis  R'y,  .  13  556 

Copper  Range  R.  R., 1  40. 

Cumberland  Valley  R.  R., 3  24 

Delaware  &  Hudson  Co., 2  64 

Department  of  Public  Works,  British  Columbia,        1  28 

Detroit  &  Toledo  Construction  Co., 1  32 

Detroit  River  Tunnel  Co., 4  264 

Elgin,  Joliet  &  Eastern  R'y, 2  72 

Erie  R.  R., 11  614 

Galveston,  Harrisburg  &  San  Antonio  R'y,  ...       1  40 

Grand  Trunk  R'y, 2  60 

Great  Northern  R'y, 6  200 

Gulf,  Colorado  &  Santa  Fe  R'y, 1  48 

Houston  &  Texas  Central  R.  R., 8  248 

Houston  Belt  &  Terminal  R'y, 3  140 

Hudson  &  Manhattan  R.  R., 10  128 

Illinois  Central  R.  R., 20  824 

Kansas  City  Terminal  R'y, 1  56 

Kentucky  &  Indiana  Terminal  R.  R., 1  56 

Lake  Shore  &  Michigan  Southern  R'y, 28  1778 

Lehigh  Valley  R.  R., 9  384 

Long  Island  R.  R., 2  68 

Louisville  &  Nashville  R.  R., 4  160 


416  GENERAL  RAILWAY  SIGNAL  COMPANY 


Number 
Name  of  Road  of  Plants 

Louisiana  R'y  &  Navigation  Co., 1 

Michigan  Central  R.  R., 6 

Missouri  Pacific  R'y, 1 

Morgan's  Louisiana  &  Texas  R.  R.  &  S.  S.  Co.,  .  1 

Nashville,  Chattanooga  &  St.  Louis  R'y,  ....  1 

New  York  Central  &  Hudson  River  R.  R.,  .    .    .  32 

New  York,  New  Haven  &  Hartford  R.  R.,  .    .    .  3 

Norfolk  &  Western  R'y, 1 

Northern  Pacific  R'y, 7 

Northwestern  Elevated  R.  R., 1 

Oregon  Short  Line, 1 

Oregon,  Washington  R.  R.  &  Navigation  Co.,   .    .  2 

Pacific  Electric  R'y, 4 

Pecos  &  North  Texas  Ry., 1 

Pennsylvania  Lines  West  of  Pittsburgh,   ....  16 

Pennsylvania  R.  R., 3 

Peoria  &  Pekin  Union  R'y, 1 

Pere    Tarquette  R.  R., 6 

Pittsburgh  &  Lake  Erie  R.  R., .  4 

Railway  Signal  Co. ,  of  Canada  (Grand  Trunk  R'y ) ,  1 

San  Francisco-Oakland  Terminal  R'y, 2 

Savannah  Union  Station, 2 

Southern  Indiana  R'y, 1 

Southern  Pacific  Co., 17 

Southern  Railway, 1 

Spokane  &  Inland  Empire  R.R., 1 

Terminal  R.  R.  Assn.  of  St.  Louis, 6 

Texas  &  Pacific  R'y, 1 

Tidewater  &  Western  R.  R 1 

Toledo  &  Ohio  Central  R.  R., 2 

Toledo  R'y  &  Light  Co., 1 

Toledo  R'y  &  Terminal  Co 2 

Toronto,  Hamilton  &  Buffalo  R'y, 1 

Union  Pacific  R.  R., 6 

Washington,  Baltimore  &  Annapolis  Electric  R'y,  1 

Western  Pacific  R'y, 6 

Wisconsin  Central  R.  R., 3 


Grand  Total, 440     21,370 


INDEX 


INDEX 


Alternating 
A 

Alternating  current  appliances,  107- 

124. 
Alternating     current      relays      (see 

relays) . 

Angles,  measures  of,  388. 
Apparatus  (see  under  name  of  mate- 
rial). 
Appendix : 

Information  for  estimating,  413, 

414. 
Interlocking  plants  installed,  list 

of,  415,  416. 
Reprint  of  Preface  from  Taylor 

(G.  R.  S.)  Catalogue  No.  1, 

405-413. 
Approach  locking,  136,  138  (see  also 

electric  locking). 
A.  R,  A.  rail  sections,  375. 
Arcs,  measures  of,  388. 
Arrester,  lightning,  371. 
A.  S.  C.  E.  rail  sections,  375. 
Avoirdupois  weight,  388. 


Ballast,  definition  of  grades  of,  273. 
Batteries : 

Primary,  caustic  soda  cell: 

Action  of,  285,  287. 

Care  of,  287. 

Description  of,  285. 

Illustration  of,  286. 

R.  S.  A.  cell,  286. 

R.  S.  A.  specifications  for,  287, 
288. 

Symbols  for,  351,  359. 

Uses  of,  285. 
Primary,  dry  cell: 

Care  of,  294. 

Description  of,  294. 

Symbols  for,  351,  359. 

Uses  of,  293. 
Primary,  gravity  cell: 

Action  of,  289. 

Care  of,  293. 

Chutes  for,  292,  293. 

Coppers  for,  R.  S.  A.,  291. 

Description  of,  289. 

Symbols  for,  351,  359. 

Uses  of,  288. 

Zinc  for,  R.  S.  A.,  290. 
Secondary,  lead  type  storage: 

Broken  jars,  153. 


Batteries 

Batteries:'— (Con.) 

Secondary,  lead  type  storage: 
Capacity   required   for  electric 

lighting,  155,  156. 
Capacity  required  for  function 

operation,  154,  155. 
Capacity  required  for  G.  R.  S. 

plants,  154-158. 
Capacity  required  for  G.  R.  S. 

plants,  table,  158. 
Capacity   required   for   indica- 
tors, locks,  etc.,  156. 
Capacity  required  for  operating 

switchboard,  155. 
Capacity,  reserve,  156,  157. 
Cell  cover  for,  146. 
Cells,  number  required  for  inter- 
locking plants,  38. 
Charging  apparatus  for,  39,  40, 

159-166. 

Charging  circuit  for,  163. 
Charging  instructions  for,  151, 

152. 

Charging  switch  for,  160. 
Charging  rate  of,  146,  159. 
Cupboards  for,  38,  158. 
Description  of,  145. 
Dimensions   of  R.    S.    A.    cell, 

146. 
Discharging,    instructions    for, 

152. 

Electrolyte  for,  146,  148,  149. 
Formula  for  determining  size  of, 

157,  158. 
Function    constants,    table   of, 

155. 

Housing  of,  37,  38. 
Illustrations   <Jf,    37,    38,    145, 

146,  158. 
'  Important    points    in    care    of, 

153,  154. 

Indications  of  trouble  in,  153. 
Initial  charge  of,  150. 
Inspection  of,  153. 
Installation,  R.  S.  A.  directions 

for,  148-151. 
Jar  for,  146. 

Large  capacity  cells  for,  151. 
Location  at  interlocking  plants, 

37. 

Low  voltage,  uses  of,  39. 
Operation,  R.  S.  A.  instructions 

for,  151-154. 
Pilot  cell  for,  151. 
Racks  for,  37,  145. 


420 


INDEX 


Batteries 

Batteries:  —  (Con.) 

Secondary,  lead  type  storage: 
Readings  of,  153. 
Reserve  capacity  required,  156, 

157. 

R.  S.  A.  directions  for  installa- 
tion, 148-151. 

R.  S.  A.  instructions  for  opera- 
tion of,  151-154. 
R.  S.  A.  specifications  for,  147, 

148. 

Sand  tray  for,  146. 
Specifications  for,  R.  S.  A.,  147, 

148. 

Symbols  for,  359. 
Trouble,  indications  of,  153. 
Two  plate  cells  for,  150,  151. 
Uses  at  interlocking  plants,  38, 

39. 

Voltage  of,  38,  39. 
Weights  of  cells  for,  146. 
Battery    charging    apparatus     (see 

charging  apparatus). 
Battery  chutes: 

Illustrations  of,  292,  293. 
Symbols  for,  351. 
Uses  of,  293. 
Weights  of,  367. 

Battery  charging  switch,  160,  161. 
Baume's     hydrometer,      compared 

with  specific  gravities,  384. 
Bearing,  for  high  or  dwarf  signal,  79. 
Belting,  373,  374. 
Blades  for  upper  quadrant  signals, 

249. 
Board   feet   required    for   trunking, 

315. 

Board  measure,  table  of,  383. 
Bolts,  dimensions  of,  380. 
Bonds,  impedance   (see  impedance 

bonds) . 

Bond  wires  and  channel  pins,  quan- 
tities required,  378. 
Boxes: 

Junction  (see  junction  boxes). 
Measuring  concrete,  323. 
Relay  (see  relay  boxes). 
Switch   (see  switch    circuit    con- 
trollers). 

Bracket  masts,  243. 
Bracket  posts  (see  posts). 
Bridge  circuit  closers ; 
Description  of,  233,  234. 
Dimensions  of,  233. 
•  Operation  of,  233,  234. 

Symbols  for,  357. 
Bridge  masts,  243. 


Circuits 


Capacity  of  storage  batteries,  154- 
158   (see  also  battery,  stor- 
age). 
Caustic  soda  cell,  285-288  (see  also 

battery,  primary). 
Centigrade  temperatures  compared 

with  Fahrenheit,  392. 
Channel  pins  and  bond  wires,  quan- 
tities required,  378. 
Charging      apparatus,      generators, 

driving  units,  etc.: 
Capacity  required,  159. 
Circuits  for,  163. 
Description  of,  39,  40. 
Dimensions  of,  168,  169. 
Efficiency  of,  159. 
Floor    space,    required    for,    159, 

169. 

Input,  159. 
Illustrations   of,    39,  40,    42,    43, 

170. 

Installation  data  for,  159-181. 
Switchboards  for,  40-46. 
Symbols  for,  359. 
Weights  of,  363. 
Charging  rheostat,  40. 
Charging  switch,  battery,  160,   161. 
Charts,  manipulation,  102,  103. 
Check  locking,  140,  141. 
Chutes,  battery  (see  battery  chutes). 
Circuits: 

Approach,  indication  and  sec- 
tion locking  in  combination, 
138. 

Approach  locking,  136. 
Alternating  current  track,  double 

rail,  273. 
Alternating  current  track,  single 

rail,  114-119. 

Battery  charging  switch,  161. 
Charging,  simplified,  163. 
Check  locking,  140,  141. 
Cross  protection,  88,  89. 
Double  rail  A.  C.  track,  273. 
Electric  locking: 

Approach,  indication  and  sec- 
tion locking  in  combination, 
138. 

Approach  locking,  136. 
Route  locking,  135. 
Section  locking  134. 
Stick,    indication    and    section 
locking  in  combination,  139. 
Stick  locking,  137. 
Interlocking  machine,  88. 


INDEX 


421 


Circuits 

Circuits: —  (Con.) 
Motor  connections: 

Model  2  switch  machine,  201. 
Model  4  switch  machine,  209. 
Operating: 

Model  2  and  3  dwarf  signals,  83, 

84. 

Model  2A  high  signal,  22-24. 
Model  2  and  4  switch  machines, 

19-22. 

Switchboards,  40-46. 
Pole  changer: 

Model  2  switch  machine,  203. 
Model  4  switch  machine,  210. 
Route  locking,  135. 
Section  locking,  134. 
Signal: 

Description  of,  22-24. 

Model  2   or  3  solenoid  dwarf, 

84. 
Model   2    solenoid   dwarf,   one 

arm,  typical,  260. 
Model   2   solenoid   dwarf,   two 

arm,  typical,  261. 
Model  3  solenoid  dwarf,  typi- 
cal, 262. 

Model  2 A,  two  position,  non- 
automatic,  simplified,  23. 
Model  2A,  two  position,  non- 
automatic,  typical,  71,  254, 
255. 

Model  2A,  two  position,  semi- 
automatic, typical,  73,  256- 
259. 

Single    rail    A.    C.    track,     114- 
119. 

Stick,     indication and     section 

locking  in  combination,  139. 
Stick  locking,  137. 
Switchboard : 

Description  of,  40-46. 
Combination  power  and  opera- 
ting, 180. 
Operating,  181. 
Operating,    simplified    diagram 

for,  45. 

Power,  176-178. 
Power,  simplified  diagram  for, 

43. 
Switch  machine: 

Description  of,  19-22. 
Double  switch  lever,  228. 
Model  2  or  Model  4,  61. 
Model  2  or  Model  4,  simplified, 

20. 

Model  2,  typical,  226. 
Model  4,  typical,  227. 


Concrete 

Circuits:  — (Con.) 
Switch  machine: 

Motor    connections,    Model    2, 

201. 
Motor    connections,    Model    4, 

209. 

Pole  changer,  Model  2,  203. 
Pole  changer,  Model  4,  210. 
Symbols  for,  354-359. 
Testing,    for   pick-up    and   drop- 
away  of  D.  C.  line  relay,  276. 
Testing,    for   pick-up    and    drop- 
away  of  D.   C.   track  relay, 
276. 
Testing,  for  resistance  of  grounds, 

372. 
Testing,    for   resistance   of   relay 

contacts,  276. 
Track: 

Alternating      current,     double 

rail,  273. 
Alternating  current,  single  rail, 

114-119. 

Written,  331-339. 
Circuit  closers,  bridge,  233,  234. 
Circuit  controllers: 

Nomenclature  for,  334-336. 
Switch    (see   switch   circuit   con- 
trollers) . 

Symbols  for,  R.  S.  A.,  356-358. 
Circular  measure,  388. 
Clearance  diagrams: 

Model  2A  dwarf  signal  and  third 

rail,  244. 

Model  2  and  Model  4  switch  ma- 
chines, 214. 
Model  4  switch  machine  and  third 

rail,  215. 
Clips,  rail,  229. 
Closers,  bridge  circuit,  233. 
Common   return  or  main  common 
wire,  19,  22,  60,  70,  83,  93, 
309. 

Concrete,  Portland  Cement: 
Box  for  measuring,  323. 
Cautions  in  use  of,  322,  323. 
Consistency  of,  321. 
Foundations  (see  foundations). 
Mixing  by  hand,  322. 
Mixing  by  machine,  322. 
Proportions  of  material  for,  321. 
Specifications,  R.  S.  A.  for: 
Cement,  325. 
Consistency,  326. 
Density  of  ingredients,  326. 
Disposition,  327. 
Facing,  327. 


422 


INDEX 


Concrete 

Concrete:  — (Con.) 

Specifications,    R.    S.   A.    for: 
Finishing,  327. 
Forms,  326. 
Freezing  weather,  328. 
General,  325. 
Gravel,  325. 
Measures,  325. 
Mixing,  326. 

Reinforced  concrete,  328. 
Sand,  325. 
Stone,  325. 
Water,  325. 
Waterproofing,  328. 
Storing  of,  321. 
Volumes  of  material  for,  324. 
Controllers,  circuit  (see  circuit  con- 
trollers). 
Control  wire  for  signals,  22,  70,  83, 

308. 
Control  wire  for  switches,   19,  60, 

308. 

Cooling  tank  (see  tanks). 
Copper-clad   wire   tables,   307    (see 

also  wire). 
Coppers  for  gravity  primary  battery, 

291. 
Copper  wire  tables,   306,   307    (see 

also  wire) . 
Cross  protection : 
Advantages  of,  26. 
Apparatus  for,  88-96. 
Circuit  breaker,  individual,  95. 
Circuit  breaker,  switchboard,  90. 
Circuits  for,  88,  89. 
Description  of,  24-26,  88-96. 
Operation  of  circuit  breaker  for, 

91,  92. 

Polarized  relays  for,  92,  93. 
Principles  of,  89. 
Safeguards,  93. 
Sectionalizing    of  plants   for,   93, 

94. 

Tests  for,  94,  96. 

Uses  of,  24-26. 

Cubic  measure,  388. 

Cupboards,  battery  housing,  38, 158. 

Cycle  of  movements: 

Model  2  switch  machine,  212. 
Model  4  switch  machine,  £13. 


Detector  bars: 

Motion  plates  for,  229. 
Rail  clips  for,  229. 
Weights  of  layouts  for,  365. 


Electro-pneumatic 

Development  of  electric  interlock- 
ing, 6. 
Diagrams : 

Illuminated  track,  105,  106. 
Track,  102,  103. 

Distances,  shipping,  between  cities 
of  U.  S.  and  Canada,  map  of, 
368. 

Direct  current  relays  (see  relays). 
Direct  current  generators  (see  gen- 
erators) . 
Dog  chart,  55. 
Dry  cell,  293,  294  (see  also  battery, 

primary) . 
Dry  measure,  388. 
Dwarf  signals  (see  signals  mechan- 
isms) . 

Dynamic  indication: 
Advantages  of,  16,  24. 
Circuits  for,  20,  23,  61,  71,  73. 
Description  of,  15,  21,  24,  60,  71, 

74. 

Safety  of,  24. 
Uses  of,  16,  24. 


Electric     interlocking     (see     inter- 
locking) . 
Electric  interlocking  machines  (see 

interlocking  machine). 

Electric  interlocking  system,  15-28. 

Electric  interlocking  system  (reprint 

from  Catalogue  No.  1 ,  Taylor 

Signal  Co.) ,  405-413. 

Electric  lighting,  127-130  (see  also 

lighting) . 
Electric  locking: 

Approach  locking,  136. 

Circuits  for,  134-139. 

Combination   of   basic   forms   of, 
138,  139. 

Definitions  of,  133. 

Description  of,  133-139. 

Development  of,  133. 

Indication  locking,  137,  138. 

Route  locking,  135,  136. 

Screw  release  for,  134. 

Section  locking,  134,  135. 

Sectional  route  locking,  135,  136. 

Stick  locking,  137. 

Time  release  for,  134. 
Electric  time  release,  134. 
Electrolyte  for  storage  batteries: 

Specific  gravity  of,  148. 

Weight  of,  146. 
Electro-pneumatic  interlocking,  5,  6. 


INDEX 


423 


Engines 

Engines,  gasoline: 
Belting  for,  373,  374. 
Cooling    tank,     connections    for, 

170,  171,  175. 

Cooling  tank,  location  of,  171. 
Description  of,  170-172. 
Dimensions  of,  169. 
Foundations  for,  169. 
Gasoline  tank  for,  171,  174,  175. 
Horse  power  of,  159,  169,  174. 
Illustrations  of,  170. 
Installation    data   for,    169,    171, 

174. 

Location  of,  171. 
Specifications,  R.  S.  A.,  for,  174, 

175. 

Speed  of,  169,  174. 
Starting,  171,  172. 
Stopping,  172. 

Tanks  for,  170,  171,  174,  175. 
Troubles,  172-174. 

Cannot  crank,  173. 

Carburetion,  172. 

Ignition,  172. 

Loss  of  compression,  172,  173. 

Loss  of  power,  173,  174. 

Mechanical  difficulties,  173. 
Water  connections  for,  170. 
Estimates,   information   to   be  fur- 
nished by  R.  R.,  413,  414. 


Fahrenheit  temperatures  compared 

with  Centigrade,  393. 
First    interlocking     installation    in 

U.  S.  A.,  5. 

Fluxes  for  soldering  and  welding,  299. 
Foundations : 

Bracket  post,  251. 

Concrete  for  (see  concrete). 

Gasoline  engine,  169. 

Ground  signal  mast,  252. 

Model  2  one  arm  dwarf  signal,  253. 

Model  2   two  arm   dwarf  signal, 
253. 

Model  2A  dwarf  signal,  253. 

Model  3  dwarf  signal,  253. 


Gasoline  engines,  169-175  (see  also 

engines) . 

Gasoline  tanks  (see  tanks). 
Gears: 

Clearance  of,  Model  2A  signal,  78. 

Formula  for,  372. 

Speed  of,  372. 


Indicating 

Generators,  direct  current: 

Capacity  of,  159,  169. 

Charging  circuits  for,  163. 

Description  of,  39,  162. 

Dimensions  of,  169. 

Engines  for  driving,  159,  169. 

Failure  to  build  up,  166. 

Fitting  brushes  to,  165. 

Foundation  for,  169. 

General     instructions     for,     164, 
165. 

Illustrations  of,  39. 

Installation  of,  162-169. 

Maintenance  of,  163-166. 

Operation  of,  162-164. 

Setting  up,  162,  169. 

Shutting  down,  164. 

Speed  of,  169. 

Specifications,  R.  S.  A.  for,  166, 
167. 

Starting,  162,  163. 

Symbols  for,  359. 

Uses  of,  39. 

Voltage  of,  162. 

Weights  of,  363. 

Gravity  cell,  288-293  (see  also  bat- 
tery, primary) . 
Grounds,  circuit  for  testing,  372. 


Hanger  irons  for  transformers,  279. 
High  Signals  (see  also  signal  mech- 
anisms) : 

Illustrations  of,  17,  22,  25,  81. 
Masts  for,  243. 
Spacing  of  arms  for,  243. 
Symbols  for,  348,  349. 
Weights  of,  365,  366. 
Horse    power   of   gasoline    engines, 

159,  169,  174. 
Hydrometer,     Baume's,     compared 

with  specific  gravities,  384. 
Hydro-pneumatic  interlocking,  5. 


Illuminated    track    diagrams,    105, 

106. 
Impedance  bonds: 

Description  of,  120,  121. 

Dimensions  of,  120,  121. 

Layouts  for,  120,  121. 

Symbols  for,  350. 

Weights  of,  367. 

Incandescent  lamps  (see  lamps). 
Indicating  relays,   alternating  cur- 
rent (see  relays). 


424 


INDEX 


Indication 

Indication,  dynamic    (see  dynamic 

indication) . 
Indication    locking,    137-139     (see 

also  electric  locking). 
Indication  magnets: 
Energy  data  for,  194. 
Illustrations  of,  51,  56. 
Resistance  of,  194. 
Indication  selector,  58. 
Indicators: 

Alternating  current: 

Description  of,  111,  112. 
Dimensions  of,  270. 
Energy  data  for,  271. 
Symbols  for,  354,  355. 
Weights  of,  366,  367. 
Direct  current: 

Battery  capacity  required  for, 

156,  157. 

Description  of,  103-105. 
Dimensions  of,  268. 
Energy  data  for,  265,  269. 
Illustrations  of,  103-105. 
Resistance  of,  265,  269 
Symbols  for,  354,  355. 
Uses  of,  103-105. 
Weights  of,  366. 
Individual  return  wire,  94. 
Installation  data   (see  under  name 

of  apparatus) . 
Installation  tools,  369,  370. 
Instructions,  installation  and  main- 
tenance (see  under  name  of 
apparatus). 
Interlocking,     introductory    article 

on: 

Electric,  G.  R.  S.  system  of: 
Applicability  of,  10-12. 
At  what  leverage  is  it  economi- 
cal to  install,  7. 
Average  sales  of  G.  R.  S.  plants, 

11. 

Comparison  of  safety  of,  9,  10. 
Cost  of  maintenance  of,  8,  9. 
Developed  by,  6. 
Distances    functions    may    be 

operated  from,  10. 
Effect  of  climatic  conditions  on, 

10,  11. 

Exploited  by,  6. 
Number  of  levers  installed,  7. 
Number  of  plants  installed,  6,  7. 
Predictions  as  to  future  instal- 
lations of,  11,  12. 
Progress  of,  6,  7. 
Proportion  of  plants  installed 
which  are  G.  R.  S.,  6,  7. 


Interlocking 

Interlocking,     introductory    article 

on:  —  (Con.) 

Electric,    G.    R.    S.    system    of: 
Reasons  for  adoption  of,  8-11. 
Safety  of,  8,  11. 
Size  of  installations  of,  11. 
Use  in  automatic  territory  of,  9. 
Use  of  track  diagrams  with,  11. 
Where  used,  6,  7,  11. 
Electro-pneumatic : 

Installation,  date  of  first,  5,  6. 
Installed  at,  first,  6. 
Plants  installed,  number  of,  6. 
Hydro-pneumatic : 

Installation  at,  first,  5. 
Invention  of,  date  of,  5. 
Plants  installed,  number  of,  5, 

6. 
Mechanical : 

Class  of  maintainers  for,  8. 
Comparison  of  safety  of,  9,  10. 
First  experimental  installation 

in  U.  S.  A.,  date  of,  5. 
Installation   in   U.    S.    A.,   by, 

first,  5. 

Installation  in  U.  S.  A.,  loca- 
tion of  first,  5. 
Installation  of,  first  important, 

5. 

Inventors  of,  5. 
Latch  locking,  first  use  of,  5. 
Limitations  of,  5. 
Origin  of,  5. 

Patents,  first  granted,  5. 
Interlocking  machine,  electric: 
Accessories  for,  58,  59. 
Arrangements   of   beds   for,    190, 

191. 

Cabinets,  length  of,  190,  191. 
Circuit   breakers   for,   individual, 

93-95. 

Circuits  for,  88. 
Control  of,  47-53. 
Description  of,  47-59. 
Dimensions  of,  186-191. 
Dog  chart  for,  55. 
Energy  data  for  indication  mag- 
nets, 194. 

Energy  data  for  lever  locks,  195. 
Features  of,  47-49. 
Frame  for,  53. 

Illustrations  of,  18,  43,  48,  49,  52. 
Indication     magnets,     operating 

data  for,    194. 
Indication  selector  for,  58. 
Individual    circuit    breakers    for, 
93-95. 


INDEX 


425 


Interlocking 

Interlocking  machine,  electric:  — 

(Con.) 

Installation  data  for,  185-195. 
Lamp   cases   and   number   plates 

for,  57. 

Legs,  number  required  and  spac- 
ing, 190,  191. 
Length  of,  190,  191. 
Lever,  description  of,  56,  57. 
Lever,  illustration  of,  51,  56. 
Lever  lock  for,  58,  195. 
Lever,  operation  of,  49-53. 
Locking  for,  53-56. 
Locking   plates   and    locking,  53, 

56. 

Maintenance  of,  188,  189. 
Mechanical  time  release  for,   58, 

59. 

Notching,  for  lever  locks,  192-194. 
Number  of  legs  required  for,  190. 

191. 

Number  plates  for,  57 
Operation  of  signal  lever,  50,  53. 
Operation  of  switch  lever,  49,  50. 
Polarized  relay  for,  57,  58,  92,  93. 
Resistance  of  indication  magnets 

for,  194. 

Safeguards  of,  47-49. 
Safety  features  of,  47—19. 
Shipment  of,  185. 
Spacing  of  legs  for,  190,  191. 
Storing  of,  185. 
Terminal  boards  for,  57. 
Testing  of,  94,  96,  188,  194. 
Time  release  for,  58,  59. 
Unit  lever  type,   description   of, 

53-58. 

Uses  of,  18,  19. 
Weights  of,  363,  364. 
Wiring  of,  typical,  88. 
Interlocking  stations: 

Arrangement  of  apparatus  in,  33. 
Construction  data,  35. 
Description  of,  31-36. 
Diagrams  of,  32,  34,  36. 
Illustrations  of,  31,  33,  35. 
Sizes  of,  31,  33. 
Symbols  for,  352. 


Joints  in  wire,  298-304. 
Junction  boxes: 

Illustrations  of,  316. 

Nails  required  for,  317. 

Symbols  for,  351. 

Weights  of,  367. 


Locking 
L 

Lamps,      incandescent      (see      also 

lighting). 

Ampere  hours  per  signal,  155,  156. 
Arrangement  for  signal  lighting, 

128. 

Power  required  for,  127. 
Symbols  for,  359. 
Types  used  in  signal  lighting,  127. 
Layouts: 

Detector  bar,  weights  of,  365. 
Impedance  bond,  120,  121. 
Switch,  218-225  (see  also  switch 

layouts) . 
Lead    type    storage   batteries    (see 

batteries,  secondary). 
Levers : 

Cross      connection      wiring      for 

double  switch,  228. 
Double  switch,  wiring  of,  228. 
Notches  for  lever  locks,  192-194. 
Signal: 

Description  of,  50,  53,  56,  57. 
Operation  of,  50,  53. 
Switch: 

Cross     connection    wiring    for 

double,  228. 

Description  of,  49,  50,  56,  57. 
Illustrations  of,  51,  56. 
Operation  of,  49,  50. 
Wiring  of  double  lever,  228. 
Lever  locks  (see  locks). 
Lighting,  electric  signal: 

Ampere  hours  required  for,  155, 

156. 

Bulbs  for,  127,  128. 
Capacity  of  battery  for,  155,  156. 
Economy  effected,  127. 
Formula  for,  156,  157. 
Lamps,  incandescent,  127,  128. 
Power    required    for,    127,    155, 

156. 

Precautions,  129. 
Recommendations  for,  130. 
Reserve  power  for,  128,  129. 
Source  of  power  for,  128,  129. 
When  economical  to  use,  127. 
Lighting  panels  (see  panels). 
Lightning  arrester,  371. 
Limitation     of     mechanical     inter- 
locking, 5. 

Linear  measure,  388, 
Liquids: 

Measure  of,  389. 
Specific  gravity  of,  385 
Locking,  check,  140,  141. 


426 


INDEX 


Locking 

Locking,  electric  (see  electric  lock- 
ing)- 
Locking    plates    and    locking,     53- 

56. 

Locking  sheet,  54. 
Locks,  lever: 

Application  to  lever,  192-194. 

Cutting  of  notches  for,  192-194. 

Description  of,  58. 

Dimensions  of,  195. 

Energy  data  for,  195. 

Illustration  of,  195. 

Installation  data  for,  192-195. 

Notching  of  levers  for,  192-194. 

Specifications  for,  192-194. 

Symbols  for,  354. 

Test  for  clearance  of,  193,  194. 


Machines : 

Interlocking  (see  interlocking  ma- 
chine) . 

Signal  (see  signal  mechanism). 

Switch  (see  switch  mechanism). 

Magnets,  indication  (see  indication 

magnets) . 

Main  common  or  common  return 
wire,  19,  22,  60,  70,  83,  93, 
309. 

Maintenance  (see  under  name  of  ap- 
paratus) . 

Maintenance  tools,  369,  370. 
Manipulation  charts,  102,  103. 
Map  of  shipping  distances  between 
cities  of  U.   S.  and  Canada, 
368. 
Masts,  R.  S.  A.  signal: 

Bracket,  dimensions  of,  243. 
Bridge,  dimensions  of,  243. 
Foundations  for,  251,  252. 
Ground,  dimensions  of,  243. 
Measures  and  weights: 

French  equivalents  of,  390,  391. 
Metric,  390,  391. 
Tables  of,  388,  389. 
Measuring  box  for  concrete,  323. 
Mechanical  interlocking   (cee  inter- 
locking, mechanical). 
Mechanical  time  release,  58,  59. 
Mechanism : 

Signal  (see  signal  mechanism) . 
Switch  (see  switch  mechanism) . 
Mercury  arc  rectifiers: 
Input  for,  159. 
Voltage  requirements  of,  159. 


Motor 

Metals: 

Fluxes  for  soldering  and  welding, 

299. 

Specific  gravities  of,  387. 
Weights  of,  387. 

Metric  measure  system,  390,  391. 
Model  2A  signal  (see  signal  mech- 
anism) . 
Model    2    dwarf   signal    (see    signal 

mechanisms) . 
Model   3    dwarf    signal    (see   signal 

mechanisms) . 
Model  2  switch  machine  (see  switch 

mechanisms). 
Model  4  switch  machine  (see  switch 

mechanisms) . 
Motion  plates,  229. 
Motors : 

Speed  of,  168. 

Starting  panels  for,  181. 

Switch: 

Connection  diagrams  for,  201, 

209. 
Cycle   of   movements    of,    212, 

213. 

Maintenance  of,  206,  211. 
Symbols  for,  359. 
Voltage      for,      operating,      159, 

162. 
Motor  generators: 

Employing  A.  C.  motor: 
Floor  space  required,  159. 
Illustration  of,  42. 
Input,  159. 
Symbols  for,  359. 
Employing  D.  C.  motor: 
Capacity  of,  168. 
Description  of,  39,  40. 
Dimensions  of,  168. 
Failure  to  build  up,  166. 
Fitting  brushes  to,  165. 
Floor  space  required  for,   159, 

168. 
General   instructions    for,    164, 

165. 

Illustrations  of,  40,  43. 
Input,  159. 

Installation  data  for,  162-168. 
Maintenance  of,  163-166. 
Setting  up,  162. 
Shutting  down,  164. 
Speed  of,  168. 
Starting  of,  162,  163. 
Symbols  for,  359. 
Weights  of,  363. 
Motor  starting  panels,  181. 


INDEX 


427 


Nails 

N 
Nails: 

Amount    required     for     junction 

boxes,  317. 
Amount    required    for    trunking, 

317. 

Sizes  of,  382. 
Weights  of,  382. 

Number    plates,    interlocking    ma- 
chines, 57. 


O 


Oiling  diagrams: 

Dwarf  bearing,  Model  2 A  signal, 

240. 
Mechanism,  Model  2A  signal,  238. 

Operating  data  (see  under  name  of 
apparatus) . 

Operating   mechanisms    (see   under 
name  of  mechanism). 

Operating  switchboards  (see  switch- 
board). 


Paint: 

Amount    required    for    trunking, 

374. 

Application  of,  374. 
Specifications,  R.  S.  A.  for,  374. 
Panels: 
Lighting : 

Dimensions  of,  182. 
Switches  for,  182. 
Weights  of,  363. 
Motor-starting,  181. 
Pilot  cell,    151    (see  batteries,   sec- 
ondary) . 
Pipe,  wrought  iron,  dimensions  of, 

381. 

Piping  for  gasoline  engine: 
Cooling  tank,  170,  175. 
Gasoline  tank,  171,  175. 
Running  water,  170. 
Plan,  track,  54. 
Plants,  power,  G.  R.  S.  (see  power 

plants) . 

Plates,  motion,  229. 
Polarized  relays: 

Description  of,  57,  58,  92,  93. 
Functions  of,  25,  92. 
Illustrations  of,  58,  92,  186,  189. 
Pole  changer: 

Model  2  switch  machine: 
Adjustment  of,  202-205. 
Connections  for,  202,  203 


R.  S.  A.  Specifications 

Pole  changer: — (Con.) 
Model  2  switch  machine: 
Illustration  of,  64. 
Installation  data  for,  202-205. 
Maintenance  of,  206. 
Movement  for,  202. 
Operation  of,  63,  64. 
Testing  of,  204,  205. 
Wiring  for,  203. 
Model  4  switch  machine: 
Description  of,  68. 
Illustration  of,  68. 
Maintenance  of,  211. 
Operation  of,  68. 
Wiring  for,  210. 

Polyphase  relays  (see  relays  A.  C.). 
Posts,  bracket: 

Foundation  for,  251. 
Masts  for,  243. 
Weights  of,  365. 

Power  interlocking    (see   interlock- 
ing). 
Power  plants: 

Batteries  for,  38,  39  (see  also  bat- 
teries) . 

Charging    apparatus    for,    39,    40 
(see  also  charging  apparatus). 
Composition  of,  37. 
Description  of,  37-40. 
Illustrations  of,  42,  43. 
Location  of,  37. 
Switchboards  for,  40-46  (see  also 

switchboards) . 

Power    switchboards     (see    switch- 
boards) . 
Primary     batteries,     285-294     (see 

also  batteries,  primary). 
Protection,  cross  (see Across  protec- 
tion) . 
Pulleys,  372. 


Racks,  battery,  illustrations  of,  37, 

145. 
Rail  clips,  E.  Z.  motion  plate  type, 

229. 

Rail  sections,  dimensions  of,  375. 
R.  S.  A.  specifications  for: 

Caustic    soda  primary    cell,   287, 

288. 

Concrete,  325-328. 
Copper  for  gravity  cell,  291. 
Electric  generator,  166,  167. 
Electric      interlocking,      extracts 

from: 
Painting,  374. 


428 


INDEX 


K.  S.  A.  Specifications 

R.  S.  A.  Specifications  for:  —  (Con.) 
Electric     interlocking,     extracts 

from: 
Trunking,   junction  boxes  and 

supports,  312,  313. 
Wire  and  wiring,  297-299. 
Gasoline  engine,  174,  175. 
Lead  type  storage  battery,  147- 

154. 
Portland   cement   concrete,   325- 

328. 
Principles   of   signal   indications, 

343. 

Signaling  practice,  343-347. 
Symbols,  348-359. 
Voltage  ranges,  282. 
Zinc  for  gravity  cell,  290. 
R.  S.  A.  standard  apparatus: 
Battery  chutes,  292. 
Battery  jar,  sand  tray  and  cover, 

146. 
Blades  for  upper  quadrant  signals, 

249. 

Bracket  post  masts,  243. 
Bridge  signal  masts,  243. 
Caustic  soda  primary  cell,  286. 
Coppers  for  gravity  battery,  291. 
Foundation  for  bracket  post,  251. 
Foundation     for     ground     signal 

mast,  252. 

Ground  signal  masts,  243. 
Spectacle,  Design  "A,"  248,250. 
Spectacle,  Design  "B,"  248. 
Zinc  for  gravity  battery,  290. 
R.  S.  A.  symbols: 

Charging  apparatus,  359. 
Circuit  controllers,  356-358. 
Circuit  plans,  354-359. 
Instruments,  357-359. 
Location,  350-353. 
Relays,  indicators  and  locks,  354, 

355. 

Signals,  348,  349. 
Switches,  derails,  etc.,  352,  353. 
Track  plans,  348-353. 
Reactance    bonds    (see    impedance 

bonds). 
Relays: 

Alternating  current: 
Boxes  for,  274,  275. 
Description  of,  109-113. 
Dimensions  of,  270,  272. 
Energy  data  for,  271,  273,  274 
Illustrations  of,  110,  112. 
Selection  of,  109,  110. 
Types  of,  110-112. 
Weights  of,  366. 


Belays 

Relays:  —  (Con.) 
Boxes  for: 

Dimensions  of,  274,  275. 

Weights  of,  367. 
Dimensions  of,  266-272. 
Direct  Current: 

Boxes  for,  275. 

Dimensions  of,  266,  268. 

Energy  data  for,  265,  267. 

Illustrations  of,  100,  101. 

Resistance  of,  265,  267. 

Testing  of,  276. 

Weights  of,  366. 
Energy  data  for,  265-274. 
Indicating: 

Dimensions  of,  270. 

Energy  data  for,  271. 

Weights  of,  366. 
Model  l.D.  C.: 

Boxes  for,  275. 

Energy  data  for,  265. 

Resistance  of,  265. 

Test    for    pick-up    and    drop- 
away,  276. 

Test  for  resistance  of  contacts, 
276. 

Weights  of,  366. 
Model  2,  Form  A,  Polyphase: 

Boxes  for,  274. 

Description  of,  110,  111. 

Dimensions  of,  272. 

Energy  data  for,  271-274. 

Illustration  of,  110. 

Test  for  resistance  of  contacts, 
276. 

Weights  of,  366. 
Model  2,  Form  B,  A.  C. : 

Boxes  for,  275. 

Description  of,  111. 

Dimensions  of,  270. 

Energy  data  for,  271. 

Illustration  of,  112. 

Test  for  resistance  of  contacts, 
276. 

Weights  of,  366. 
Model  3,  Form  B,  A.  C.: 

Boxes  for,  275. 

Description  of,  111,  112. 

Dimensions  of,  270. 

Illustration  of,  112. 

Test  for  resistance  of  contacts, 
276. 

Weights  of,  366. 
Model  9,  D.  C.: 

Boxes  for,  275. 

Dimensions  of,  266. 

Energy  data  for,  267. 


INDEX 


429 


Belays 

Relays:  —  (Con.) 
Model  9,  D.  C.: 

Illustrations  of,  101. 
Resistance  of,  267. 
Test    for    pick-up    and    drop- 
away,  276. 
Test  for  resistance  of  contacts, 

276. 

Weights  of,  366. 
Model  Z,  Form  B.  A.  C. : 
Boxes  for,  275. 
Description  of,  112. 
Dimensions  of,  270. 
Energy  data  for,  271. 
Illustration  of,  112. 
Test  for  resistance  of  contacts, 

276. 

Weights  of,  366. 
Motor,  Three  Position,  D.  C.: 
Boxes  for,  275. 
Description  of,  98,  100,  101. 
Dimensions  of,  268. 
Energy  data  for,  267,  268. 
Illustration  of,  100. 
Test  for  resistance  of  contacts, 

276. 

Weights  of,  366. 
Polarized  (see  polarized  relay). 
Symbols  for,  354,  355. 
Testing: 

Pick-up  and  drop-away  of,  276. 

Resistance  of  contacts  for,  276. 

Three  Position  D.  C.  Motor  (see 

Relay,  Motor) : 
Relay  boxes: 

Dimensions  of,  274,  275. 
Symbols  for,  351. 
Weights  of,  367. 
Release,  time  (see  time  release) . 
Route  locking,   135,    136    (see  also 
electric  locking). 


S 


Safeguards: 

Cross   protection   system,    24-26, 

93. 

Dynamic  indication,  24. 
G.  R.  S.  system,  24-26. 
Interlocking  machine,  47-49. 
Switch     operating     mechanisms, 

61-63. 

Tests  for  cross  protection,  94,  96. 
Safety  of  G.  R.  S.  electric  interlock- 
ing: 

Comparison  with  mechanical,  8. 
Cross  protection,  89. 


Signals 

Safety  of  G.  R.  S.  electric  interlock- 
ing:—  (Con.) 
Dynamic  indication,  24. 
Features  important  to,  15. 
Test  of,  94,  96. 
Sand: 

Concrete,  325. 
Measuring  box  for,  323. 
Quantities  of,  for  concrete,  324. 
Specific  gravities  of,  386. 
Weights  of,  386. 
Screw  release  (see  time  release) . 
Secondary   batteries  (see  batteries, 

secondary). 
Sectionalizing  of  G.  R.  S.  plants,  93, 

94. 
Sectional   route   locking,    135,    136 

(see  also  electric  locking) . 
Section  locking,  134,  135  (see  also 

electric  locking). 
Selector,  indication,  58. 
Semaphore   spectacles   (see  specta- 
cles). 

Shipping  distances  between  cities  of 
U.  S.  and  Canada,  map  of, 
368. 
Shipping  weights,  363-367  (see  also 

weights) . 
Signaling  practice: 

American,  trend  of,  11. 
Definitions  of,  343-347. 
Principles  of  signal  indications, 

343. 
R.    S.    A.   recommendations   for, 

343. 
Signals: 

Automatic  block: 

Basis  of  adoption  in  America, 

9. 

Percentage  of  American   Rail- 
ways signaled,  9. 
Type  first  used,  9. 
Blades  for  upper  quadrant,  249. 
Bracket  masts  for,  243. 
Bridge  masts  for,  243. 
Control  wire  for,  22,  70,  83,  308. 
Dwarf  (see  signal  mechanisms). 
Electric  lighting  for,  127-130. 
Foundations  for,  251-253. 
Ground  masts  for,  243. 
Illustrations  of  dwarf,  16,  74,  75, 

83,  86. 
Illustrations  of  high,  17,  22,  25, 

81. 

Indications,  principles  of,  343. 
Interlocking  (see  signal  mechan- 

3). 


430 


INDEX 


Signals 

Signals:  —  (Con.} 

Mechanisms    (see  signal  mechan- 
isms). 

Spectacles  for,  248. 
Symbols  for,  348,  349. 
Weights  of,  365,  366. 
Signal  blades,  249. 
Signal   lighting,   127-130    (see   also 

lighting) . 
Signal  mechanisms: 

Circuits  for  (see  circuits,  signal). 
Control  wire  for,  22,  70,  83,  308. 
Dwarf,  solenoid  (see  solenoid 

dwarf  signals). 

Dynamic  indication  for  (see  dyna- 
mic indication). 
Foundations  for,  251-253. 
Installation  data: 

Adjustments,  237,  239,  241. 

Dimensions,  242,  245-247. 

Foundations  for,  251-253. 

Lubrication  of,  239. 

Masts  for,  243. 

Method  of  taping  wires  to,  244. 

Storing  of,  237. 

Spectacle  adjustment  for,  239. 

Tests  of,  240. 
Maintenance  of: 

Adjustments,  237,  241. 

Lubrication,  239,  241. 

Oiling  diagrams,  for,  238,  240. 

Spectacle  adjustments  for,  239. 

Tests  for,  240. 
Masts  for,  243 
Model  2 A  non-automatic: 

Adjustment  of,  237,  241. 

Circuits  for,  23,  71,  254,  255. 

Clamp  bearing  for,  79. 

Control  of,  70-72. 

Control  wire  for,  22,  70,  308. 

Description  of,  22-24,  77-79. 

Description     of     circuits     for, 
22-24. 

Dynamic     indication,     advan- 
tages of,  24. 

Dwarf  bearing  for,  79. 

Gears,  clearance  of,  78. 

Illustration  of,  76. 

Installation  of,  237. 

Length  of  control  wire  for,  308. 

Lever  operation  for,  50,  53. 

Lubrication  of,  239. 

Maintenance  of,  241. 

Method  of  taping  .wires  to,  244. 

Names  of  parts  for.  76. 

Oiling  diagrams  for,   238,  240. 

Operating  data  for,  241. 


Signals 

Signal  Mechanisms :  —  (Con.) 
Model  2A,  non-automatic : 

Simplified  circuits  for,  23. 

Size  of  control  wire  for,  308. 

Spectacle  adjustment  for,  239. 

Storing  of,  237. 

Tests  for,  240. 

Typical    circuits    for,    71,    254, 
255. 

Weights  of,  366. 
Model  2A,  semi-automatic: 

Adjustment  of,  237,  241. 

Circuits  for,  73,  256-259. 

Clamp  bearing  for,  79. 

Control  of,  72-75. 

Control  wire  for,  22,  83,  308. 

Description  of,  81,  82. 

Dimensions  of,  242. 

Dwarf  bearing  for,  79 

Dynamic  indication  advantages 
of,  24. 

Gears,  clearance  of,  78. 

Illustrations  of,  80,  81. 

Indication   spring   attachment, 
82. 

Installation  of,  237. 

Length    of     control    wire    for, 
308. 

Lever  operation  for,  50-53. 

Lubrication  of,  239. 

Maintenance  of,  241. 

Method    of    taping    wires     to, 
244. 

Names  of  parts  for,  80. 

Oiling  diagram  lor,  238. 

Operating  data  for,  241. 

Size  of  control  wire  for,  308. 

Spectacle  adjustment  for,  239. 

Spring  attachment,  indication, 
82. 

Storing  of,  237. 

Tests  for,  240. 

Typical  circuits   for,  73,    256- 
259 

Weights  of,  366. 

Model  3,  operating  data  for,  241. 
Model  7,  operating  data  for,  241. 
Motor  driven  (see  Model  2A  sig- 
nals). 

Operating  and  indicating  circuits, 

description  of,  22-26,  70-75. 

Solenoid     dwarf      (see     solenoid 

dwarf) . 

Symbols  for,  348,  349. 
Typical  circuits  for  (see  circuits). 
Types  of,  70. 
Weights  of,  365-366. 


INDEX 


431 


Single  Bail 

Single  rail  A.  C.  track  circuits,  114- 
119  (see  also  track  circuit 
A.  C.). 

Solenoid  dwarf  signals: 
Model  2: 

Circuits  for,  84,  260,  261. 
Control  of,  83,  84. 
Control  wires  for,  83,  308. 
Description  of,  83-85. 
Dimensions  of,  246,  247. 
Foundations  for,  253. 
Illustration  of,  83. 
Length    of    control   wires    for, 

308. 

Names  of  parts  for,  85. 
Operating  data  for,  241. 
Operating  mechanism  for,  85. 
Size  of  control  wires  for,  308. 
Weights  of,  366. 
Model  3: 

Circuits  for,  84,  262. 
Control  of,  83,  84. 
Control  wire  for,  83,  308. 
Description  of,  86,  87. 
Dimensions  of,  247. 
Foundation  for,  253. 
Illustration  of,  86. 
Length    of    control    wires    for, 

308. 

Names  of  parts  for,  87. 
Operating  data  for,  241. 
Operating  mechanism  for,  87. 
Size  of  control  wire  for,  308. 
Weights  of,  366. 
Soldering : 

Fluxes  for,  299. 
Wire  joints,  298,  303. 
Specific  gravity  of: 
Brick,  etc.,  386. 
Cement,  etc.,  386. 
Comparison    with    Baume's    Hy- 
drometer, 384. 
Electrolyte,  146. 
Liquids,  385. 
Metals,  387. 
Sand,  etc.,  386. 
Stone,  etc.,  386. 
Wood,  385. 
Specifications    (see   under  name   of 

material) . 
Spectacles : 

Blades  for,  249. 
Clamp  bearing  for,  79. 
Dimensions  of,  248. 
Dwarf  bearings  for,  79. 
Torque  curves  for,  250. 
Square  measure,  table  of,  388. 


Switch 

Stakes: 

Specifications  for,  312,  313. 
Weights  of,  367. 
Stations,    interlocking,    31-35    (see 

also  interlocking  station) . 
Stick  locking,  137  (see  also  electric 

locking) . 
Stone: 

Concrete,  size  for,  325. 
Measuring  box  for,  323. 
Quantities  for  concrete,  324. 
Sizes  for  concrete,  325. 
Specific  gravity  of,  386. 
Weights  of,  386. 
Storage     batteries     (see     batteries, 

secondary) . 
Switches: 

Battery  charging,  description  and 

circuits,  160,  161. 
Nomenclature  of,  336. 
Panels  for  (see  panels). 
Symbols  for,  357,  358. 
Switchboards: 
Operating : 

Cross  protection  circuit  breaker 

for,  90-92. 

Description  of,  45,  46. 
Dimensions  of,  181. 
Illustrations  of,  43,  44. 
Lighting  panels  for,  182. 
Location  of,  37. 
Polarized  relay  for,  92,  93. 
Simplified  circuits  for,  45. 
Weights  of,  363. 
Wiring  for,  181. 
Power : 

Description  of,  40-45. 
Dimensions  of,  176-180. 
Illustrations  of,  41-43. 
Location  of,  37. 
Lighting  panels  for,  182. 
Manipulation  of,  176-180. 
Simplified  circuits  for,  43. 
Starting  panels'for,  181. 
Weights  of,  363. 
Wirings  for,  176-180. 
Switch  boxes  (see  switch  circuit  con- 
trollers). 
Switch  circuit  controllers : 

Connections  to  switch  pointfor,232. 
Model  3,  Form  D: 
Dimensions  of,  230. 
Illustrations  of,  97. 
Weights  of,  366. 
Model  4: 

Description  of,  69. 
Illustrations  of,  69. 


432 


INDEX 


Switch 

Switch  circuit  controllers:  —  (Con.) 
Model  5,  Form  A: 

Adjustable  cam  for,  231. 

Cam  for,  231. 

Description  of,  98. 

Dimensions  of,  231. 

Illustrations  of,  98,  99. 

Weights  of,  366. 
Symbols  for,  357. 
Weights  of,  366. 
Switch  layouts: 

Model  2  switch  machine: 

Double  slip  switch,  223. 

Hayes  derail,  220. 

Movable  point  frog,  224. 

Movable  point  frog  with  double 
slip  switch,  225. 

Single  slip  switch,  222. 

Single  switch,  218. 

Slip  switches,  222,  223. 

Split  point  derail,  219. 

Weights  of,  364,  365. 

Wharton  or  Morden  derail,  221. 
Model  4  switch  machine: 

Double  slip  switch,  223. 

Hayes  derail,  220. 

Movable  point  frog,  224. 

Movable  point  frog  with  double 
slip  switch,  225. 

Single  slip  switch,  222. 

Single  switch,  218. 

Slip  switches  222,  223. 

Split  point  derail,  219. 

Weights  of,  364,  365. 

Wharton  or  Morden  derail,  221. 
Switch  machine: 
Model  2: 

Adjustment  of,  201-204. 

Advantages  of  dynamic  indica- 
tion of,  24. 

Circuits  for,  20,  61,  226,  228. 

Clearance  compared  with  Model 
4  switch  machine,  214. 

Control  of,  60. 

Control  wire  for,  19,  60,  308. 

Cross  protection  for,  24-26. 

Cycle  of  movements  of,  212. 

Description  of,  64-67. 

Description     of     circuits     for, 
19-22. 

Dimensions  of,  216. 

Double  lever  for,  wiring  of,  228. 

Drilling  of  lock  rod  for,  205. 

Dynamic  indication  for,  21,  24, 
60,  67. 

Energy  data  for,  214. 

Illustrations  of,  21,  62,  63. 


Switch 

Switch  machine:' — (Con.) 
Model  2: 

Indication  selector  for,  58. 

Installation  data  for,  199-206. 

Layouts  for,  218-225. 

Length  of  control  wire  for,  308. 

Lever,  illustrations  of,  51,  56. 

Lever,  operation  of,  49,  50. 

Maintenance  of,  199-206. 

Motor  connections  of,  201. 

Names  of  parts  for,  65,  200. 

Operating  data  for,  214. 

Operation  of,  60-67. 

Operation  of  controlling  lever 
for,  49-50. 

Pole  changer  for,  64. 

Pole  changer  movement  for, 
202. 

Pole  changer  wiring  for,  203. 

Safeguards  of,  61-63. 

Simplified  circuit  for,  20. 

Size  of  control  wire  for,  308. 

Spring  attachment  for,  63. 

Storing  of,  199. 

Switch  circuit  controllers  for 
(see  switch  circuit  control- 
lers). 

Testing  of,  204,  205. 

Tie  framing  for,  19Q. 

Time  of  operation  of,  22,  214. 

Tools  for  maintenance  of,  369, 
370. 

Typical  circuits  for,  20,  61,  226, 
228. 

Weights  of,  365. 
Model  4. 

Adjustment  of,  209,  210. 

Advantages  of  dynamic  indica- 
tion of,  24. 

Circuits  for,  20,  61,  227,  228. 

Clearance  between  third  rail 
and,  215. 

Clearance  compared  with  Model 
2  switch  machine,  214. 

Control  of,  60. 

Control  wire  for,  19,  60,  308. 

Cross  protection  for,  24-26. 

Cycle  of  movements  of,  213. 

Description  of,  67-69. 

Description  of  circuits  for, 
19-22. 

Dimensions  of,  217. 

Double  lever  for,  wiring  of,  228. 

Dynamic  indication  for,  21,  24, 
60. 

Energy  data  for,  214. 

Illustrations  of,  16,  19,  67. 


INDEX 


433 


Switch 

Switch  machine:  —  (Con.) 
Model  4: 

Indication  selector  for,  58. 

Installation  data  for,  207-211. 

Layouts  for,  218-225. 

Length  of  control  wire  for,  308. 

Lever,  illustrations  of,  51,  56. 

Lever,  operation  of,  49,  50. 

Maintenance  of,  211. 

Motor  connections  of,  209. 

Names  of  parts  for,  66,  208. 

Operating  data  for,  214. 

Operation  of,  67-69. 

Operation   of  controlling  lever 
for,  49,  50. 

Pole  changer  for,  68. 

Pole  changer  wiring  for,  210. 

Safeguards  of,  61-63. 

Simplified  circuit  for,  20. 

Size  of  control  wire  for,  308. 

Storing  of,  207. 

Switch  circuit  controllers  for,  69. 

Testing  of,  210,  211. 

Third  rail  clearance  for,  215. 

Tie  framing  for,  207. 

Time  for  operation  of,  214. 

Tools  for  maintenance  of,  369, 
370. 

Typical    circuits    for,    20,    01, 
227,  228. 

Weights  of,  365. 
Symbols  for,  350. 

Switch  mechanisms  (see  switch  ma- 
chine). 
Switch  operating  mechanisms   (see 

switch  machine) . 
Symbols : 

Lever    contacts,    Model    2  inter- 
locking machine  336. 
R.  S.  A.  standard: 

Charging  apparatus,  359. 

Circuit  controllers,  356-358. 

Circuit  plans,  354-359. 

Instruments,  357-359. 

Location,  350-353. 

Relays,    indicators    and    locks, 
354,  355. 

Signals,  348,  349. 

Switches,  derails,  etc.,  352,353. 

Track  plans,  348-353. 


Tables  (see  under  name  of  material) . 
Tanks: 

Cooling,  for  gasoline  engine: 
Capacity  of,  174. 


Track 

Tanks:  — (Con.) 

Cooling    for     gasoline     engine: 
Dimensions  of,  174. 
Location  of,  171. 
Specifications,  R.  S.  A., for,  174, 

175. 

Water  connections  for,  170. 
Gasoline : 

Capacity  of,  174. 
Dimensions  of,  174. 
Location  of,  171. 
Specifications,    R.    S.    A.,    for, 

174-175. 

Taylor  (G.  R.  S.)  electric  interlock- 
ing   system    (reprint),    405- 
413. 
Temperature : 

Comparison    of    Fahrenheit    and 

Centigrade  scales,   392,  393. 

Effect  on  G.  R.  S.  electric  plants, 

10,  11. 
Effect  on  mechanical  plants,  10, 

11. 
Terminal  boards: 

Interlocking  machine,  57. 
Transformer,  122,  123. 
Tests  (see  under  name  of  apparatus) . 
Thermometer  scales: 

Comparison    of    Fahrenheit    and 

Centigrade,  392,  393. 
Threads,    U.    S.    standard     screw, 

380. 
Tie  framing: 

Model  2  switch  machine,  199. 
Model  4  switch  machine,  207. 
Time  release: 

Electrical,  133,  134. 
Mechanical,  58,  59. 
Symbols  for,  358. 
Tools,  maintenance,  369-370. 
Towers    (see  interlocking  stations). 
Track  circuits: 

Alternating  current,  double  rail: 
Bonds  for,  120,  121. 
Diagram  of,  273. 
Energy  curves  for,  273. 
Impedance  bonds  for,  120,  121 
Relays  for  (see  relays  A.  C.). 
Transformers    for    (see    trans- 
formers) . 

Alternating  current,  single  rail: 
Advantages  of,  114. 
Central    energy    scheme,    117- 

119. 

Description  of,  114-119. 
Diagrams  of,  116,  117. 
Energy  required  for,  115. 


434 


INDEX 


Track 

Track  circuits : — (Con.) 

Alternating  current,  single  rail: 
Illustration  of,  118. 
Limitations  of,  114,  115. 
Relays  for  (see  relays  A.  C.). 
Transformers    for     (see    trans- 
formers) . 

Types  of,  116,  117. 
Direct  current: 

Batteries      for      (see     battery, 

primary) . 

Bond  wires  for,  378. 
Boot  leg  for,  316. 
Channel  pins  for,  378. 
Indicators  for,  103-106  (see  also 

indicators) . 
Locking  circuits  for  (see  electric 

and  check  locking). 
Relays  for  (see  relays,  D.  C.). 
Tests  for,  relays,  276. 
Tools  for,  370. 
Wire  sizes  for,  297. 
Track  diagrams,  102-106. 
Track  indicators: 
Alternating  current: 

Description  of,  111-113. 
Dimensions  of,  270. 
Energy  data  for,  271. 
Weights  of,  366,  367. 
Direct  current: 

Description  of,  103-105. 
Dimensions  of,  268. 
Energy  data  for,  265,  269. 
Illustrations  of.  103-105. 
Weights  of,  366. 
Track  plans: 

Dog  chart  for,  55. 
Illustrations  of,  54. 
Locking  sheet  for,  54. 
Symbols  for,  348-353. 
Track  tools,  list  of,  370. 
Track      transformers      (see      trans- 
formers) . 
Transformers : 

High  tension  line: 

Capacity  of,  280,  281. 
Combinations  of,  122,  123. 
Description  of,  122,  123. 
Dimensions  of,  279. 
Hanger  irons  for,  279. 
Illustrations  of,  122. 
Ratings  of,  280,  281. 
Terminal  board  for,  122. 
Weights  of,  363. 
Windings  for,  122,  123. 


Weight 

Transformers:  —  (Con.) 
Secondary  track: 

Description  of,  123,  124. 

Dimensions  of,  282. 

Illustration  of,  123. 

Rating  of,  282. 

Weight  of,  363 

Windings  for,  123. 
Symbols  for,  359. 
Trunking: 

Area  of  groove  in,  314. 

Board  feet  for,  315. 

Bootleg  for,  316. 

Capacity  of,  314. 

Capping  for,  315. 

Construction  of,  312,  316. 

Dimensions  of,  315. 

Hooks  required  for,  317. 

Joints  in,  312,  315. 

Junction  box  for,  313,  316. 

Nails  required  for,  317. 

Paint  required  for,  374. 

Screws  required  for,  317. 

Sections  of,  315. 

Specifications  for,  312,  313. 

Stakes  for,  312,  313. 

Supports  for,  312,  313. 

Surfacing  of,  315. 

Table  for  determining  size  of,  314. 

Weights  of,  367. 

W 

Weight: 

Avoirdupois,  388. 
Brick,  etc.,  386. 
Cement,  etc.,  386. 
Electrolyte,  146. 
Lag  screws,  382. 
Metals,  387. 
Nails,  382. 
Pipe,  381. 
Sand,  etc.,  384. 
Shipping : 

Battery  chutes,  367. 

Bracket  posts,  365. 

Cantilever  bracket,  366. 

Charging  apparatus,  363. 

Detector  bar  layouts,  365. 

Dummy  mast,  366. 

Dwarf  signals,  366. 

Fixed  arm,  366. 

Generators,  363. 

Impedance  bonds,  367. 

Indicating  relays,  366. 

Indicator  groups,  366. 

Indicators,  366,  367. 


INDEX 


435 


Weight 

Weight:  — (Con.) 
Shipping : 

Interlocking     machines,     363, 
364. 

Junction  boxes,  367. 

Lever  lock,  364. 

Lighting  panels,  363. 

Locking,  364. 

Motor  generators,  363. 

Posts  for  relay  boxes,  367 

Relay  boxes,  367. 

Relays,  366. 

Signals,  complete,  365,  366. 

Signals,  dwarf,  366. 

Signals  mechanism,  Model  2A, 
366. 

Stakes,  367. 

Switchboards,  363. 

Switch  circuit  controllers,  366. 

Switch  circuit  controller  rods, 
366. 

Switch  layouts,  364,  365. 

Switch  machines,  365. 

Transformers,  363. 

Trunking,  367. 
Stone,  etc.,  386. 
Storage  battery  cells,  146. 
Tables  of,  388,  389. 
Water,  389. 
Wire,  306,  307. 
Wood,  385. 

Welding,  fluxes  for,  299. 
Wire: 

Aluminum  compared  with  copper, 

310. 
Common  return,  19,  22,  60,  70,  83, 

93,  309. 

Control  for  signals,  22,  70,  83,  308. 
Control  for  switches,  19,  60,  308. 
Copper  (see  also  rubber-covered) : 

Carrying  capacity  of,  310. 

Compared  with  aluminum,  310. 

Fluxes  for  soldering,  299. 

Gauge  for,  305. 

Hard  drawn,  table  of,  307. 

Interlocking    specifications,    R. 
S.  A.,  297-299. 

Joints  in,  298-304. 

Soft  drawn,  table  of,  306. 

Soldering  of,  303. 

Splicing  of,  298-304. 

Taping  of,  303,  304. 


Zinc 

Wire:— (Con.) 

Copper-clad,  table  of,  307. 
Gauges  for,  305. 
Individual  return,  94. 
Iron,  table  of,  306. 
Rubber-covered  copper: 
Conduit  for,  size  of,  314. 
Interlocking    specifications,    R. 

S.  A.,  297-299. 
Joints,  298-304. 
Manufacturer's   Engineers' 

standard,  dimensions  of,  311. 
R.  S.  A.  standard,  dimensions 

of,  311. 

Soldering  of,  304. 
Splicing  of,  298-304. 
Tags  for,  299. 
Taping  of,  303,  304. 
Trunking  for,  size  of,  314. 
Steel,  table  of,  306. 
Symbols  for,  359. 
Weights  of,  306,  307. 
Wirings  (see  circuits,  also  name  of 

apparatus) . 
Wood,  specific  gravity  and  weight 

of,  385. 
Written  circuits: 

Description  of,  331,  332. 
Nomenclature  of: 
Circuits,  334-336. 
Circuit  controllers,  334-336. 
Indicator  contacts,  335. 
Knife  switch,  336. 
Latch  contact,  336. 
Lever    contacts,  numbering   of 

336. 

Operated  units,  332-334. 
Push  button,  336. 
Relay  contacts;  335. 
Terminals,  336. 
Time  release  contacts,  335. 
Wires,  337,  338. 
Illustrations  of,  338,  339. 
Plans  involved,  331,  332. 
Use  of,  331. 
Wrought  iron  pipe: 
Dimensions  of,  381. 
Weight  of,  381. 


Zinc  for  gravity  battery  cell,  290. 


14  DAY  USE 

RETURN  TO  DESK  FROM  WHICH  BORROWE1 

LOAN  DEPT. 

This  book  is  due  on  the  last  date  stamped  below,  or 

on  the  date  to  which  renewed. 
Renewed  books  are  subject  to  immediate  recall^ 

__i^OiJS91 

>ihC'D  LD 


REC'b  uWN  1  3  1995 


FEB 





LD  21A-50m.l2,'60 


General  library    . 
University  of  California 
Berkeley 


